Note: Descriptions are shown in the official language in which they were submitted.
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IDENTIFIABLE MARKING COMPOSITIONS AND METHODS
Field of~the Invention
The invention is directed to compositions and methods for
identifiably marking an object. Specifically, the invention provides for
marking an
object with a marking composition containing a taggant which can be correlated
with a particular source of the marking substance. In one embodiment, a
marking
substance of the invention can be sprayed on a person at the scene of a crime
and
permit subsequent identification and verification that the person was at the
scene of
the crime.
Background of the Invention
Personal defense compositions for repelling an assailant are known.
Such products can also be used by police, military or other authorities for
controlling
I S unruly crowds or disruptive persons. Some well known products for this use
include
tear gas or CHEMICAL MACE~. When sprayed on a human or animal, these
products may cause pain and discomfort to the attacker, however, they may not
effectively disable the attacker.
A more potent composition that has become popular in recent years
and adopted by many law enforcement personnel and the public in general is
pepper
spray including capsicum and its chemical equivalents, such as capsaicin. _See
~.
U.S. Patent No. 5,217,708. While often effective in disabling an attacker, one
of the
problems with pepper spray is that it can also be lethal. In fact, reports
have been
filed documenting the death of persons following being sprayed with pepper
spray.
Small canisters of pepper spray are available to certain members of
the general public which may be carried in a pocket, purse, or held in the
hand, so
that it may be used as a deterrent to a crime against the person or against
one's
property. Unfortunately, one of the disadvantages of pepper spray is that it
is so
potent, that even an unintentional or accidental release can produce
catastrophic
results. It is because of this potential for catastrophic results that airline
passengers
are required to reveal the possession of canisters of pepper spray, and
airline
personnel routinely confiscate canisters of pepper spray from passengers if it
becomes known that a canister is being carned.
Another disadvantage of presently available personal defense
products is that even if an assailant is fended off by the product, it may
nevertheless
be difficult to later identify and apprehend the assailant. That is, some
presently
available personal defense products do not provide a means to conclusively
identify
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2
the assailant if his/her face or some other characteristic of the assailant
was not
noticed by the victim during the criminal act.
One well publicized means for subsequent identification of an
assailant that is available today is DNA analysis and correlation with the DNA
of a
suspected assailant. However, the use of DNA technology requires access and
possession of some physical part of a suspect believed to be the perpetrator
of a
crime. If available, analysis of the DNA present in skin, hair, body fluids,
etc.,
collected at the scene of a crime, has been used to identify a suspected
assailant.
Unfortunately, it can often be difficult for law enforcement personnel to
secure the
possession of such samples to enable analysis and comparison with the DNA of a
suspect. Moreover, although DNA may be useful for identification of a suspect
in
some situations, external visualization of the suspect, even immediately after
commission of a crime, does not reveal that the suspect has been involved in a
crime, thus increasing the likelihood that the suspect can flee and
potentially avoid
1 S prosecution.
Methods for marking a liquid composition for later identification or
association of the liquid with a prior location are known. For example, U.S.
Patent
No. 5,474,937 discloses adding a chemical element or organic compound labeled
with a non-radioactive isotope to a bulk supply of a chemical substance, such
as
petroleum, for later identification of the source of the chemical substance.
However,
while the patent discloses methods for bulk products, it lacks guidance for
identifying the source of a substance originating from a particular unit of a
personal
use type product. Moreover, while the chemical substance may be marked, the
mark
used is generally invisible to the naked eye.
U.S. Patent No. 1,787,995 discloses a method for identification of
lubricating oil type liquids by including in the liquid small markers, such as
letters or
symbols, having the same specific gravity as the lubricating oil. In addition
to other
deficiencies, this disclosure is also directed to bulk materials.
Accordingly, there is a need for an identifying composition that
reliably provides for later identification of a discrete source of the
composition.
Moreover, there is a need for an identifying composition that readily
acknowledges
that a material containing the composition is identifiable as to its source.
In addition, in the area of personal defense or crowd control, there is a
need to deter disruptive or criminal activity with reduced chance of injury to
the
victim, perpetrator or uninvolved third parties. There is also a need for
increasing
the likelihood that the perpetrator of a crime can be identified for
apprehension and
prosecution of the crime. These and other needs are addressed by the present
invention.
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Summary of the Invention
The present invention is directed to compositions and methods for
marking an object for later correlation with the source of the composition.
The
compositions and methods disclosed herein are particularly advantageous for
identifying a discreet unit source of the identifying composition. The
disclosed
composition can be included in personal defense type products for humane, and
in
some cases, conspicuous marking of the perpetrator of a crime. Alternatively,
the
composition and methods of the invention can also be used with presently
available
personal defense type products to facilitate identification and apprehension
of an
assailant.
In one embodiment, the invention provides a taggant which can be
included with a composition for identifying a particular source of the
composition or
taggant. A taggant of the invention includes one or more indicators
constituting an
identifiable chemical "signature" that is unique for each particular unit
container of
the taggant or composition. The taggant composition can be correlated with a
particular source and a source identification code for the particular
composition
recorded for later correlation with a particular unit ar canister of the
chemically
coded composition.
In one embodiment, the invention provides a marking substance
which can be selectively expelled from a unit container source. According to
this
embodiment, in addition to a taggant, a marking substance can also include a
earner
such as a polymer resin matrix and a visibly detectable label such as a
colored
pigment, dye, or fluorescent compound.
The marking substance of the invention can be included in a single
unit canister for selective dispensing of the marking substance in the form of
a spray
or stream that may be propelled a considerable distance from the canister.
Known
propellants can be included in the marking substance for propelling the
marking
substance from the canister. In addition, other materials such as drying
agents and
fillers can be used in a composition of the invention.
A composition containing a taggant of the invention can be used to
mark many different types of objects. In one embodiment, the invention
provides
for innocuous marking of a human. Such an application provides law enforcement
officials with efficient means for subsequent identification and apprehension
of a
perpetrator of a crime. In some embodiments, the conspicuous nature of a
marking
substance of the invention can also act as a deterrent to criminal activity.
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4
Detailed Description of the Invention
The present invention is directed to marking an object with a
composition that can later be used to identify the source of the composition.
The
identifiable composition includes a taggant that can be correlated with a
discrete unit
source of the composition. One source of the composition can be a personal use
size
container from which the composition may be expelled as a spray or stream. In
one
embodiment, a composition of the invention is a marking substance which
includes a
carrier for tenaciously adhering the substance to a surface and a label that
renders the
marking substance visibly detectable.
It will be noted that in several places throughout the specification,
guidance is provided through lists of examples. In each instance, the recited
list
serves only as a representative group. It is not meant, however, that the list
is
exclusive.
In some embodiments, a marking substance of the invention can be
carried by, for example, law enforcement officials for humanely marking the
hair,
skin, clothing, etc. of a large number of people for later identification and
verification that an individual was at the location where marking occurred.
Alternatively, a herein disclosed marking substance can be carried as a
substitute for
repellent type personal defense products, allowing a victim to atraumatically
mark
an assailant for later identification. In yet another embodiment, a taggant of
the
invention can be included with capsasicum or other repellent type personal
defense
product for repelling an assailant as well as for facilitating subsequent
identification
and apprehension of the assailant.
As used herein, an "identifiable composition" is a composition which
permits retrospective correlation of the composition with a particular source
of the
composition. An identifiable composition of the invention can be applied to
many
objects for marking. As used herein, the term "object" includes animate
objects such
as humans, plants and animals as well as inanimate objects such as
construction
materials, shipping crates, weapons, drugs, money, automobiles, etc. A
composition
of the invention is typically applied to the surface of an object. Examples of
surfaces which can be marked on a human include, hair, skin, clothing, etc.
A composition of the invention includes a "taggant" which provides
for retrospective correlation of the composition with the source of the
taggant or
composition. As used herein, a taggant can include a "chemical code"
comprising
one or more "indicators." The indicators of a particular taggant represent a
subset of
indicators selected from a larger predetermined set of indicators. The
presence
and/or absence of each of the predetermined indicators in a subset of
indicators is a
unique combination of indicators thus providing a unique chemical code for
each
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taggant. Preferably, for any particular field of marking use; the chemical
code of a
taggant is not duplicated. That is, each unit source of a composition
including a
taggant of the invention has a unique chemical code.
A record of the unique chemical code of each taggant can be
5 maintained by a manufacturer and assigned a "source identification code"
identifying the particular chemical code of a particular taggant. The chemical
code
can be represented in the source identification code using any suitable system
including, without limitation, numeric or alphanumeric symbols such as a
serial
number, acronyms, bar code labels, etc. The source identification code can be
associated with a unit source of the taggant by marking the source, marking
the
package of the source, including a registration card with the source that
recites the
source identification code, etc. A composition of the invention can also be
part of a
kit including, for example, a registration card reciting the source
identification code
and/or a retroreflective sticker for application to home, auto or other
location to
announce use of a taggant product.
As used herein, an "indicator" may be any chemical or biological
material which can be identified when a composition containing the indicator
is
analyzed to determine the indicator's presence. Known methods of analysis can
be
used to identify the presence of the indicator including, for example,
separation,
extraction, spectrophotometry, fluorometry, mass spectrometry, gas
chromatography, high pressure liquid chromotography, nuclear magnetic
resonance
spectroscopy, etc. It will be appreciated that the term "indicator" includes
an
"integrity indicator" as discussed below.
Generally, an indicator of the invention can be non-reactive. As used
herein "non-reactive" means that the indicator does not participate in any
chemical
reaction that may occur in the composition and it does not undergo chemical
change
or transformation which would preclude subsequent identification of the
indicator's
presence in the composition. In addition, preferably the indicator will not
cause
substantial irritation or injury to the surface on which it may be applied. An
indicator
of the invention can be selected from various families of innocuous compounds
including, for example, esters, amides, alcohols, etc. Suitable indicators
which are
relatively innocuous when applied to an animate object such as a human can,
for
example, be selected from flavorant and/or fragrance compounds including
acetates
such as: benzyl; phenethyl; anisyl; geranyl; a-methyl bensyl; p-tolyl;
vanillan; amyl;
2-methyl butyl; isoamyl; hexyl; nonyl; decyl; heptyl; octyl; lauryl;
cyclohexyl; di-
methyl; prenyl; trans-2-hexenyl; linalyl; neryl; and tetrahydrofurfuryl.
Compounds
not contained in the acetate family may also be utilized.
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6
In addition, for some uses, it may be advantageous to enrich an
indicator with a stable atomic isotope. .In some embodiments, an isotopically
enriched indicator can serve to authenticate that the indicator is from a
particular
source. For example, if there is a possibility that a composition including
the
indicator may be comingled with another source of the compounds) selected as
an
indicator, such as a natural source, using an isotopically enriched indicator
will
permit confirmation that the taggant indicator is from the identifiable
composition.
Examples of suitable stable istopes include hydrogen-2, carbon-I3, oxygen-17,
fluorine-19, nitrogen-15 and oxygen-18.
To ensure that the chemical code of a taggant has not been
compromised, an "integrity indicator" can be used. As used herein, an
"integrity
indicator" is an indicator included in a chemical code that has increased
vulnerability
to loss, damage or other failure of detection under the conditions in which
the
taggant may be used. Factors which can affect a failure of detection of an
integrity
I S indicator under particular conditions include, for example, molecular
size, molecular
weight, chemical structure, electrical charge, volatility, etc. Thus, for
example, an
indicator having a volatility greater than other indicators of the taggant can
be added
to the taggant. The presence of the added volatile indicator in subsequent
analysis
can confirm that the remaining indicators of the taggant have not been
compromised
by volatilization.
A herein described taggant can be admixed with other components to
increase the duration of detectability of the taggant, render a tagged
composition
visible, increase adhesiveness, increase the surface area that can be coated
by the
tagged composition, etc. Generally, for any particular composition, the
taggant is
selected for ability to disperse homogeneously throughout the composition.
Homogeneous dispersion ensures that analysis of any portion of a composition,
before or after application, will reveal the entire chemical code correlated
with a
specific container. In some preferred embodiments, an identifiable composition
can
maintain a homogenous dispersion for at least 6 months to 2 years without the
need
for shaking or other mixing to redisperse the taggant.
A marking substance of the invention can also include a "carrier."
One example of a carrier is a polymer resin matrix, such as an adhesive or
coating
resin. The carrier can function to facilitate adherence of the taggant to a
surface on
which the composition is applied and/or preserve or "encapsulate" the taggant
in a
robust environment. That is, the carrier can preferably withstand a
significant
amount of abuse and contamination without loss of chemical code information or
degradation of the taggant constituents after the carrier has "set-up." In the
present
context, "set-up" includes curing or drying. As used herein the term "cure"
means
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7
that the carrier has completed reactions that render the carrier infusible or
chemically
inert, such as completion of cross-linking reactions. The term "dry" means
that
solvents used to keep the resin carrier in a dispensable state, such as a
liquid, are no
longer present (e.g., evaporated). In some embodiments, it may be advantageous
for
the carrier to leave a "trail of evidence" by transferring or smearing to
additional
surfaces before or after set up. Thus, for example, the marking substance can
transfer before drying or after drying but before curing. Additionally, or
alternatively, the marking substance can transfer by exfoliating from, for
example, a
human assailant, over a period of several days, after curing.
The dry time of the carrier can be varied. In some embodiments, dry
time can be measured in days. In some embodiments, a dry time of between about
1
to 600 seconds, preferably about 30 to 240 seconds is selected as it is fairly
quick
yet will remain in an undried state long enough to create additional "tell-
tale"
evidence such as permanent fingerprints, similar to fingerprints left on a
paint brush
1 S handle when painting. The carrier can also be selected to preserve the
taggant,
perhaps for many years, thus increasing longevity and the amount of evidence
available in, for example, a criminal investigation.
In a preferred embodiment the earner has a viscosity range of about
50 to 1000, preferably about 100 to 200 centipoise at ambient temperatures. In
some
embodiments for human application, the carrier can be chosen for its ability
to
adhere to human hair, skin, clothing, and most other similar surfaces that it
may
come into contact with while curing. Examples of suitable earners include
alkyds,
acrylates, styrenes, etc. One preferred earner is a polymer resin matrix, such
as a
phenolic modified alkyd, available as product number 057-5703 from McWhorter
Technologies, Minneapolis, MN.
A marking substance can also include additives. Such additives
include a solvent for adjusting the viscosity of the carrier. Examples of
suitable
solvents include acetone, xylene, perchloroethylene, etc. Filler materials
such as
fumed silica, diatomaceous earth, titanium dioxide, etc., can also be added.
One
filler material, titanium dioxide, can be added to enhance visibility of a
resin earner.
Other additives include one or more drying agents such as cobalt, zirconium
and/or
other metallic driers which function to enhance cure time of the composition
when
sprayed onto an object, such as a person or clothing, or when exposed to the
atmosphere.
A marking substance of the invention can also include a label. As
used herein, a "label" refers to a compound that renders the substance visibly
detectable. This includes, for example, colored pigments, dyes, fluorescent
compounds visible with or without ultraviolet light rays, etc. In an
embodiment
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8
including a polymer resin matrix for human application, preferably, the label
will
adhere to, and visibly mark human skin, hair, fingernails, etc., for a period
of several
days despite the exfoliation of the resin matrix that may occur during this
interval.
Preferably, the label is not easy to remove by the use of commonly known
aqueous
or organic solvents such as soap and water, rubbing alcohol, minerals spirits,
etc.
One example of a suitable label are dyes sold under the trademark DayGlo~,
available from DayGlo Corporation, Cleveland, OH. Other suitably aggressive
colorants can be used in a dye/resin combination of a marking substance such
as
Hansa yellow pigment, or iron oxide yellow pigments, etc.
The use of a label that is a bright colorant can advantageously provide
visual identification of a criminal assailant. This is particularly true if
the colorant is
conspicuous such as a bright yellow or glowing fluorescent color. Since many
police apprehensions of criminals are carried out with the assistance of the
general
public, a visible colorant can act to alert the public that a marked
individual has
probably been involved in a crime, thus facilitating the apprehension process.
For
example, in one embodiment, the inventors foresee a common color scheme for
use
on packaging, advertising, and included with an identifiable composition to
create
public familiarity, thus increasing the efficacy of a marking substance
product as a
deterrent to criminal activity. By combining a label with a resin matrix, the
visual
identif cation aspect of the label can be prolonged.
In some embodiments a taggant composition of the invention can be
supplied in a personal use container. As used herein, a "personal use
container"
refers to a container that can be carried by a person, for example, in a
purse, on a
belt, in a coat pocket, etc. Preferably, the container is hand operated for
selective
release of the composition from the container using an actuator button.
Suitable
actuator buttons are known and include nozzles such as safety nozzle systems
presently in use: Examples of suitable actuator buttons include No. 8-PA
available
from Omega USA.
A larger "personal use container" for use by, for example, law
enforcement officials, can include a larger hand operated device about the
size of a
fire extinguisher. In addition, it is foreseeable that a marking substance of
the
invention can be in a container located for public access such as presently
available
fire extinguishers for emergency use.
The container can also include an aerosol propellant such as propane,
isobutane, dimethylether, compressed nitrogen, compressed carbon dioxide, or
other
similar propellants or mixtures thereof, at appropriate pressures for
dispensing the
product from the container. A hand-held container can be sized for holding a
total
volume of non-propellant ingredients of approximately 1 to 3 fluid ounces.
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9
Containers utilizing greater volume may of course be utilized. A high flow-
rate
valve such as manufactured by Precision Valve Co. can be used to expel the
majority
of the contents within a short period of time, for example, 1 to 10 seconds.
Thus, for
example, an identifiable composition of the invention can be packaged in a
small
aerosol container and used as a hand-held unit for personal security.
The actuator button is preferably of such design that it can spray the
material from the container to a target object in a splattering, "shotgun"
type pattern,
or a concentrated stream with a range of about 5-20 feet, preferably at least
about 8
feet. The design of the activator button preferably minimizes the possibility
of
accidental discharge while maintaining convenience and ease of use. Several
good
safety nozzle designs are currently in use on available consumer and law
enforcement products, and could be used for the substance described herein.
One example of a suitable personal use container is an aluminum
tube-type, such as model number 40-2, available from Peerless Tube Co.
Preferably,
1 S the canister is equipped with a locking nozzle and collar, such as model
numbers 8-
PA and 18-NAS, respectively available from Omega USA, and a valve assembly
such as model #AR-74 available from Seaquist. This type of canister, or a
similar
canister, can be adapted for use with any one of a number of different aerosol
propellants, such as listed above, or other similar propellants or mixtures
thereof,
which may be used at various appropriate pressures or selected special
pressures to
fulfill a specific need. For instance, individual containers may be equipped
with
nozzles that may be adjustable to produce a spray of the compound when
expelled
from within the canister, or to squirt a stream of the compound for an
extended
distance from the canister.
As discussed above, one aspect of the invention provides an
improved method and means of identifying and apprehending suspected criminal
assailants. Thus, in one embodiment, the invention comprises individually
formulated chemical lots of pressure-sprayable compounds contained in
individual
canisters. In one preferred embodiment, the pressurized container includes a
Garner,
such as a polymer resin matrix; a visible label; and a taggant. Additional
constituents may include solvents, fillers, drying agents, etc.
However, a herein described taggant may also be included in known
personal defense spray products. These products, such as pepper spray or
compounds including a tear gas such as ortho-chlorobenzalmalononitrile or
chloroacetophenone (e.g., MACE~), can be disabling to the person sprayed to
provide an opportunity for the victim to escape or secure help in further
subduing an
assailant. The inclusion of a taggant, with or without other components
disclosed
herein, can further provide for identification of the assailant.
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A substance or composition bearing a taggant unique to each
individual unit container, serves to add a conclusive link between a specific
container and surfaces that the taggant-containing material from that
container
adheres to, such as skin, hair, clothing, carpet, wood, concrete, automobile
paint,
glass, plaster walls, etc.
The following examples are presented for purposes of explanation,
and are not intended to limit the number of different embodiments of the
invention
that may be constructed.
EXAMPLES
10 EXAMPLE 1:
A three fluid ounce aerosol canister was filled with two fluid ounces
of McWhorter 57-5703 alkyd resin matrix material diluted to 50% solids in
acetone.
One gram of Keystone Keyplast Yellow R, #806-043-50, a bright fluorescent dye,
was added to the resin for visibility. A unique chemical code consisting of
ester
flavorants was formulated directly into the canister. The esters were added to
effect
a detectable concentration in the resin matrix. This enables definitive
retrospective
analysis by gas chromatograph and/or mass spectrometry. For dispensing
purposes,
the indicator esters are diluted 1:10 in xylol as a solvent. At this
concentration,
additions of one tenth of one milliliter of each required diluted indicator
ester will
provide a detectable amount in the two fluid ounces of the mixture. Following
admixture in a specific canister, an aerosol valve, cup, and dip-tube assembly
is
crimped onto the canister as is common in the aerosol industry. Compressed
nitrogen at 125 psi is added to the canister to serve as a propellant. A spray
nozzle is
then assembled onto the valve as is commonly known in the aerosol spray
industry.
For this Example, the carboxylic esters are chosen from the group
including geranyl acetate, nonyl acetate, decyl acetate, linalyl acetate, di-
methyl
acetate, cyclohexaneethyl acetate, lauryl acetate, citronellyl acetate,
vanillin acetate
and cyclohexyl acetate. Each indicator represents the binary numerical places
l, 2,
3, 4, 5, 6, 7, 8, 9 and 10, respectively. A unique decimal serial number, say
276, is
printed on the canister. The binary equivalent of the decimal numeral 276 is
100010100. Thus, the binary numerical places 3, S and 9, counting from right
to
left, have ones (1), and the other places 1, 2, 4, 6, 7 and 8, have zeroes
(0). The
indicators that represent the numerical places 3, S and 9, are decyl acetate,
di-methyl
acetate and vanillin acetate, respectively. These constituents are added to
the
canister. Each canister is assigned its own unique serial number, and thus,
its own
chemical code corresponding to that serial number. This ensures that the
content of
each canister is unique and traceable to that canister alone.
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11
In addition, an integrity indicator, such as heptyl acetate can be added
to the composition in all canisters to later confirm the presence of all
taggants
originally formulated into each unique chemical code. In the present example,
heptyl acetate was chosen because it has been shown to be lost from the resin
matarix
before other indicators . The higher volatility will cause the concentration
of the
heptyl acetate to decrease faster than the concentration of any of the other
individual
carboxylic esters listed above. During retrospective analysis of a given resin
sample,
detection of the presence of the integrity indicator confirms the presence of
all other
individual taggant constituents formulated into that given chemical code.
EXAMPLE 2:
In a real life scenario, consider that the canister of Example 1 is in the
possession of an individual, to be used for the marking and identification of
a
prospective criminal-attacker, should the occasion arise. The individual is
subsequently attacked and the individual discharges the contents of the
canister onto
the hair, skin and clothing of the attacker. Before the resin matrix has
dried, the
attacker handles obj ects such as a doorknob and a steering wheel leaving
fingerprints
visually enhanced by the fluorescent resin matrix. While the resin is in the
uncured
state, it also collects hairs and fibers from the scene of the crime, adhering
them to
the attacker.
The marked attacker is later visually identified by the fluorescent dye.
A ten-milligram sample of the resin matrix is collected from the attacker and
analyzed to reveal the unique chemical code. A match between the chemical code
formed by the indicators on the suspected attacker and the chemical code
derived
from the indicators in the victim's canister conclusively places the suspect
at the
scene of the crime. This chemical code also matches the serial number printed
on
the canister. Further investigation shows that the fingerprints left at the
scene and in
the suspects car are those of the suspect. Hair and fibers from the crime
scene are
also found on the suspect. Thus, in this scenario, the visibility of the resin
matrix on
the marked attacker has aided in the identification and apprehension of the
suspect.
The adhesive properties of the resin matrix and the individual unique chemical
code
of the taggant in the canister have provided evidence that can be used for
conviction
of this attacker.
EXAMPLE 3:
A canister such as that of Example 1, is carried by a woman while
jogging in a secluded area of a public park. The woman is attacked. During the
struggle she discharges the contents of the canister onto the attacker,
however, about
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12
25% of the contents is sprayed or smeared on the woman, her clothing, and the
jogging path. The attacker attempts to wipe the sticky resin from his face,
hair, and
clothing, transferring his hair and clothing fibers, mixed with resin to his
hands.
Further struggle with the woman transfers his hair and fibers from his hands
to the
woman's face and arms.
Realizing he has been "tagged", the attacker takes the canister from
the woman in an attempt to conceal evidence and flees. Criminal investigators
collect samples of the resin from the victim and the crime scene. They also
find the
attacker's hair on the victim. Chemical analysis of the resin matrix samples
reveal
that taggant esters geranyl acetate, nonyl acetate, lauryl acetate and
cyclohexyl
acetate, representing numerical places 1, 2, 7 and 10, are present. This
corresponds
to the binary number 100100011, which is equivalent to the decimal serial
number
579 printed on the canister. Analysis also detects the heptyl acetate
integrity
indicator, which confirms the presence of all indicators originally formulated
in the
resin matrix being analyzed, ensuring that the complete chemical code is
intact.
Two days later, one of the attacker's neighbors sees the fluorescent
resin matrix material adhered to the hair behind the attacker's ear.
Recognizing the
fluorescent resin as a known criminal marking material, the neighbor calls the
police. Analysis of resin matrix samples taken from the suspect reveal the
presence
of the heptyl acetate integrity indicator, and the esters geranyl acetate,
nonyl acetate,
lauryl acetate, and cyclohexyl acetate, correlating with the binary number
10010001.
This places the attacker at the scene of the crime and allows criminal
investigators to
focus their investigation.
EXAMPLE 4:
A resin matrix sample including a chemical code taggant is collected
from the cuticles of a crime suspect's fingers. Chemical analysis reveals the
presence of the heptyl acetate integrity indicator, along with the presence of
three
other esters forming the chemical code of this sample. If the integrity
indicator has
not evaporated or been washed away by solvents, the other individual esters in
the
particular formulation are also present. Thus, the presence of the integrity
indicator
can confirm that the three esters are the only taggant constituents used in
this
chemical formulation, thus matching the sample taken from the suspect's
cuticles,
and identifying him (or her) as having been at the scene of the crime.
EXAMPLE 5:
A fluorescent yellow resin substance is recognized and collected at a
crime scene. Chemical analysis reveals the presence of the integrity
indicator,
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13
heptyl acetate, along with indicators correlating with binary number places 1,
3 and
8. Because the integrity indicator is present, it is known that esters
representing
binary number places l, 3 and 8 were the only esters used to formulate the
chemical
code in question, indicating that the true binary numerical analog is
10000101. This
corresponds to the decimal serial number 133 printed on the canister from
which the
resin matrix sample emanated.
EXAMPLE 6:
A canister such as described in Example 1 is purchased and given to
an eight year old child. The serial number on the canister is recorded by the
parent
and a registration card is filed with a law enforcement agency. The
registration card
can recite the child's name and address along with a source identification
code such
as a serial number and canister manufacturer. Six months later the child
disappears
from its neighborhood. Criminal investigators interview known pedophiles in
the
area. During an interview, investigators recognize a fluorescent paint-like
substance
on the hands of the person being interviewed. A search warrant is obtained,
leading
to the discovery of more evidence. Chemical analysis of the resin found on the
suspect and in his car reveal the chemical code registered to the missing
child. The
suspect is arraigned on charges of child abduction.
EXAMPLE 7:
A mugger threatens a man, ordering him to hand over his wallet. The
man sprays the mugger with a substance from a canister such as the one
described in
Example 1. Knowing he has been tagged with a visible, unique chemical code,
the
mugger flees. A police report is filed, recording the source identification
code, e.g.,
a serial number, of the canister from which the substance was sprayed. One
week
later the mugger is arrested in connection with a different crime. The
arresting
officer recognizes small but visible traces of the marking substance under the
mugger's fingernails. A warrant is obtained to search the mugger's home. More
of
the fluorescent resin material is found in the drain of the mugger's shower.
The
resin material is collected and analyzed, revealing a chemical code profile.
Investigators contact the manufacturer of the substance to obtain the serial
number
that coincides with the chemical code. The serial number given by the
manufacturer
corresponds with the serial number on the previous police report, thus
connecting
the mugger to the previous crime.
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14
EXAMPLE 8:
A field of fifteen "indicators" can be chosen from FDA approved
carboxylic esters. Many of these esters can be found in commercially available
consumer products and thus presence of the indicators associated with the
presence
of a particular identifiable composition may be argued to be a contaminant. To
belay any doubt at a later time of the origin of the esters, the esters can
each be
partially enriched with a stable isotope, for example, C-13. According to this
example, assume that the natural concentration of C-13 in carboxylic esters is
less
than 1%. Hence, the fifteen taggant esters are enriched to have a level of C-
13
greater that 1 %, for example, of 2% or higher to distinguish them as products
from
the specific source of manufacture. In a given situation, perhaps an
enrichment of
5% or more may be required so that after the taggant is diluted in a
composition to
be tagged, chemical analysis will reveal a detectable enrichment level of C-
13. To
accomplish this, the selected esters are chemically constructed using C-I3 as
the
labeling isotope, and mixed with the same non-labeled esters to a
concentration of
5% or more of each ester. The resulting esters, with a C-13 enrichment greater
than
natural levels, are then used as individual indicators in the formulation of
the final
chemical codes.
EXAMPLE 9:
Another method for authenticating the source of the indicators of a
taggant is to chemically modify the indicators in a manner that creates an
atypical or
unique structure of the indicator. For example, in the case of the esters
recited in
Example 1, the esters can be halogenated using known esterification methods.
Such
methods include, for example, use of a halogenated acetic acid such as
chloroacetic
acid. The halogenated form of the ester can be readily differentiated from the
common esters using, for example, a gas chromatograph equipped with an
electron
capture detector.
EXAMPLE 10:
The present example illustrates the use of an isotopically labeled
indicator for authenticating the source of an indicator in a taggant. Assume,
for
purposes of the example, that an accused suspect is on trial and a marking
substance
such as that described in Example 2 was collected from the suspect's hair. The
defense argues that the chemical code contained in the marking substance is
inconclusive because the evidence may have been contaminated. The prosecution
has the evidence examined by mass spectral analysis. Analysis shows that the
indicators of the chemical code are isotopically enriched to a concentration
greater
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than the natural levels for the indicators. This authenticates the source of
the esters
as being from the marking substance rather than a contaminating source.
In one aspect, the invention also contemplates a registration system
5 for source identification codes. To create an accurate registration system,
each unit
container of a marking substance is preferably imprinted with an individual
source
identification code that may be cross-referenced to the chemical code defined
by the
indicators or taggant in that particular container. The registration system
can then
provide the identification of the buyer of the canister containing the taggant
of the
10 substance when analyzed. Registration cards can be supplied with the
product to
facilitate this process, or the source identification code may be included as
part of
the information contained in an appropriate bar code imprinted on each
container or
on a label thereon.
It will be apparent to one of ordinary skill in the art that many
15 changes and modifications can be made in the invention without departing
from the
spirit or scope of the appended claims.
