Note: Descriptions are shown in the official language in which they were submitted.
~2S~
Background of the _nvention
To those familiar with instant adhesives, it's
no surprise that their vapors can expose fingerprints
with the white residue caused by monomer "blooming".
In ~act, efforts to reduce this undesirable behavior
date from the early days of cyanoacrylate technology.
However, it was left un~il much later to discover
that this same process could be turned to the noble
task of apprehending criminals through fingerprint
identification. In 1978 the Tokyo Metropolitan Police
are reported to have hosted a demonstration of cyano-
acrylate fuming for development of fingerprints by
criminologists of the Japanese National Police Agency.
In May of 1979, ~etective Inspector N. Edmunds and L.
Wood of Northamptonshire (England) Police are reported
to have observed that fingerprints were developed when
they repaired a black plastic developing tank with
Loctite Super GlueT . Within a month, they reported
their findings to a regionaI police conference.
Constable Paul Bourdon of the North Bay Ontario
Police Force was an early practitioner of the method
and invented a ~uming system which generates vapor in
one chamber and pumps it into another which contains the
evidence under investigation. His system is described
in U.S. Patent 4,297,383.
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Frank Kendall of the IJ.S. Bureau of Alcohol,
Tohacco and ~irearms, developed an improvement in
the method which uses cotton treated sodium hydroxide
to accelerate the generation of vapors.
description of this technique is given in Identifi-
cation News, June 19&2, page 3.
The use of heat to accelerate generation of
cyanoacrylate vapors for fingerprint development use
has also been reported. Identification News,
January 1983, page 9, and May 1983, page 10.
The cyanoacrylate vapor technique has become an
accepted method for fingerprint deve,lopment. In
several cases, identifications have been made on
evidence for which no previous methods had been
workable. Recently, evidence provided by this
method has been accepted in a ~ansas court leading
tc criminal conviction. ~bele, Identification News,
February 1983, page 12.
Recognized benefits of using cyanoacrylate
monomers to develop fingerprints which have beer.
discovered to date are as follows:
a) Development of latent prints on objects where
other methods have failed;
b) development of prints on difficult surfaces
such as polyethy]ene bags or electrical tapes;
c) print images produced are easier to handle than
powder-dusted prints which may blow away;
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d) large enclcsed areas, such as automobile
interiors can be fumed for prints.
The significant benefits of the cyanoacrylate
fingerprint development techniaue, however, have
been acccmpanied by other notable disadvantages.
These disadvantages include the instant bonding of
cyanoacrylate adhesives to skin and clothing when
contacted by evidence techrlicians. Also, the
typical low viscosity cyanoacrylate adhesive used in
the prior techniques is easily spilled or dripped.
This not only contributes to inadvertent bonding of
clothes and skir. but can also result in damage to
the evidence. ~nitially, without acceleration of
vapor generation, it has been reported that full
development of a print takes at least akout five
hours and can take as long as 90 days.
h7ith acceleration of vapor generation, other
disadvantages have heen identified as follows:
Disadvanta~es of Sodium Hydroxide Acceleration:
1. Sodium hydroxide is a poison and corrosive,
and can cause damage~to skin if not mixed
wearing gloves.
2. Preparation time is substantial.
3. The technique provides a small amount of
fumes for the amount oi adhesive used.
Most of the adhesive polymerizes, within
the saturat~ed pad or as visible white~
smoke, rather than being
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evaporated ir,to the atmosphere within the
chamber. The polymerized white smoke does
not react with the latent print.
Fumes from the pads rise to the top of the
chamber, then filter down, failing to
provide uniform exposure of the objects
being processed to the vapors.
Disadvantages of Heat_Acceleration:
1. Temperature settiny carl be critical. Too
hot may result in overdevelopment of the
print and iailure of the adhesive to
polymerize within the print. Too cool may
xesult in failure of the adhesive to be
ahsorbed into the chamber as quickly as
desired, re~uiring longer processing.
2. Use in smaller chambers, even in small
amounts, may result in overdevelopment if
the items being processed are not closely
monitored.
3. Various methods of using heat as an
accelerant also heat the entire chamber,
affecting vinyls and~plastics (especially
black vinyl tape~s). ~ ~
4. Minor accidents involving the use of
heated objects may result in burns or
damage to the chamber.
SU~ r~ 1~ At;~
The present invention ls an improvement of
.
~s~s
developing latent fingerprints with cyanoacrylate
vapors. The method comprises subjecting an article
suspected of containing a latent fingerprint to
cyanoacrylate vapors generated from a thin film of a
storage-stable composition comprising a cyanoacrylate
mcnomer and a thixotropic additive in an amount
effective to render the composition substantially
nonflowable on a vertical surface. This thixotropic
composition is preferably also stakilized against
polymerization to a degree where the adhesiveness of
the composition is substantially reduced.
In a preferred embodiment of the invention, the
15 gel composition is contained in a thin envelope or
pouch which is peeled open to expose two inner
surfaces coated with a thin layer of the gel. The
resu]ting high surface area generates vapor rapid]y
and evenly for prolonged periods of time. This
20 rapid and sustained vapor generation can result in
deve~opment of latent fingerprints which are not
developed by prior art methods.
The following advantages have been identified
25 for the inventive process over the prior art methods
of generating vapors.
1. No poisons or corrosives.
2. No preparation time.
3. Produces an even amount of exposure to the
adhesive evaporated within the chamber
over a 20-minute plus time period.
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~;22~85
4. Provides evaporation from a larger surface
area than previous methodc.
5. Room temperature opexation. No critica~
effects of minor variations in the temper-
ature.
6. No heat to destroy vinyls or plastics.
7. Overdevelopment does not occur in a short
period of time. Items can be left ir. the
chamber up to one hour over the amount of
time required without los~ Gf ridge detail
(items, as in previous methods, should not
be placed closer than 3 inches to the
envelope).
8. No burns or damaged chambers.
9. No spillage of adhesive or contamination
of evidence.
10. Substantial]y reduces complexity of
cyanoacrylate use making it feasible fGr
~20 use in the field by minimally trained
technicians.
n~escription of The Drawings
Figure 1 is a side sectional view of a cyano-
acrylate se] containing package preferred for use in
the inventive method.
Figure 2 is a bottom plan ~iew of the package
of figure 1.
Figure 3 is a plctorial view of the opened
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package showing cyanoacrylate coated inner surfaces
exposed to the air for vapor generation.
Detailecl Description of The Invention
Cyanoacrylate Gel Formulatio_
A hish vapor pressure cyanoacrylate monomer
must be utilized in order to give adequate monomer
vaporization. Methyl cyanoacrylate and ethyl
cyanoacrylate are the preferred monomers. Ally]
cyanoacrylate and isopropyl cyanoacrylate are
suitable monomers which nlay also be utilized alone
or in a mixture.
The formula~ion of a storage-stable nonflowahle
cyanoacrylate gel has long keen a difficult problem
because of the ease c~f polymerization of the monomer.
Thus, while many formulations employing typical
silica thixotropes have been reported in the art,
such composiitons typically are intended to be
utilized immediately or have been subsequently shown
to have poor shelf sta~ility. While it has been
discovered that storage stable formulations of
certain silicas highly treated with dimethyldichloro-
silane can be macle, the high degree of surface
treatment so dramatically affects the thixotropic
capability of the silica that nonflowa~le gels
cannot be preparedO More recently, it has been
discovered that certain uniquely treated silicas
produce storage-ssab1e nonflowable gel compositions.
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Compositions of cyanoacrylate monomers with ~hese silicas,
are described more fully in U.S. Patent No. 4,477,607.
The compositions of the above patent are suitable for
use in the inventive method and provided the initial
embodiments o~ the gel used in the inventive method.
Working with the initial gel formulations, it was
discovered that the stabilizer level could be substan-
tially increased over that typically used in cyanoacry-
late adhesive formulations. Since the fingerprints are
developed by polymerization of monomer vapors, the level
of stabilizer in the base composition was not critical.
Therefore, the stabilizer level in the base composition
could be increased to the point where adhesive bonding
is significantly reduced without affecting fingerprint
development performance. This is especially advantageous
in fingerprint development since the possibilities of
monomer contact are substantial. The monomer containers
are open and have substantial surface areas (typically
2"X2" in previous methods, about 13"Xl4" in the prefer-
red embodiment of the invention).
Suitably stabilizer levels are such that thewell-known instantaneous fingerstick caused when
fingers having cyanoacrylate monomer spilled thereon
contact an article or each otber does not occur for
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-- 10 --
at least 10 seconds. This delay gives time to wipe
off spilled material. Additionally, the stabiliza-
tion allows some of the fumed silicas which previously
had been discovered unsuitable for use in storage-stable
cyanoacrylate adhesive formulations to he used in
the fingerprint developing gels of the invention.
The thixotropic formulations used in the
inventive method are substantially nonflowable as
thin films on a vertical polyethylene surface.
~ he thixotropy of the compositions can be
estimated by taking Brookfield viscosity measurements
ir. cps (mPas) at room temperature (about 21C) at
2.5 and 20RPM. Compariscn of the ratios of the two
measurements for various samples indicates ~hat
relative thixotropy of those samples. A sample
having a 2.5/20RP~I viscosity ratio (thixotropic
ratioJ cf I is not thixotropic. To be suitable for
use in the invention, the composition ger,erally
should have a thixotropic ratic of about 2.5 or
more, preferably 3 or more.
2S
A convenient test for determining substantial
nonflowability as that term is used herein, is to
spot a 0.2 gram sample of a thixotropic composition
on a vertical polyethylene surface on an area of
about 3/2" x 1/2" ~12.7cm x ~2.7cm) and observe the
flow with time. If the sample flows no more than
about l" in five minutes, it will generally be
suitable for u~e ln ~he inveneive method. Pre erably
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the sample should not move even an inch over a
several hour observation ~eriod.
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Examples of suitable formulations are contained
in Tah].e I.
TABLE I
Ethyl Cyanoacrylate w/ A B C D E F G
100 ppm S~2, 100 ppm
methane sulfonic acid
an~ 1000 ppm hydroquinone 92 92 92 60 94 88 --
Methyl Cyanoacrylate w/
200~ ppm methane sulfonic
acid and 1000 ppm hydro-
quinone -~ -- 88
Aerosil R972 1 8 -- -- -- -~
Aerosil R976 1 -- 8 -- -- -- -- --
Aerosil R805 ~ - 8
Aerosil R200 -- -- -- -- 6 -- --
Cabosil N70-TS ~ -- -- -- -- -- 6 6
Pol~vinylidine Fluoride 3 -- -- ~- 40 -- -- --
Polymethylmethacrylate -- -- -- -- -- 6 6
Room T~mp. Visc. 2.5RPM
~cps x 103) 22 12 80 100 640 96 _
Thixotropic Ratio 2.5RPM/ ~ :
20RP~: 3.0 3.0 5.7 5.3 7.3 5 7
Aerosil is a trademark: of DeGussa Corp. R972,
R976, R805, and 200:are fumed silicas with
respective treatments: diméthyldichlorosilane,
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octyltrimethoxysilane, and untreated.
Cabosi~ is a trademark of Cabot Corp. N70-TS is
fumed silica treated with polydimethylsiloxane.
3 See US Pat. 4,105,775.
The various formulations have different monomer
evaporation characteristics deperiding on thixotrope
and level. Formulations such as C and E are preferred
for evaporation charactertistics because they give
faster evaporation rates and almost total evaporation
at room temperature before polymerizatior. from thin
films on polyethylene. Composition D had the
s~owest evaporation and lowest total evaporation,
presumably because of the high polymer content.
Generating The VapGr~
In order to obtain rapid and uniform vapor
generation at room temperature, it is desirable that
the monomer be distributed over a high surface area.
~hereas development techniques using pourable liquid
monomers must contain the monomer in a bowl on a
horizontal surface, the nonflowable formulations
used in the inventive method do not have to be
contained. ~hey may be thinly spread on vertical
surfaces, e.g., on a sheet of paper or plastic film
hung on a wall, without feax of damage to evidence
or personnel.
~ preferred package for the fingerprint developing
gels is shown in Figures 1-3. The package generally
designated by the numeral 10 is an envelope constructed
from three sheets, 12, 12a and 13 of a laminate
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material having a polyethylene inner surface. The
laminate is preferably a paper/polyethylene/aluminum-
/polyethylene laminate material. A bonding primer
between the various layers is preferably included so
that the material does not delaminate when the
envelope is peeled cpen. Three heat sealed edges 14
bond sheets 12 and 12a together. Sheet 13 is heat
sealed between the end flaps 16 and 16a at the
fourth end of sheets 12 and 12a, thereby forming a
closed envelope structure with separable but sealed
end flaps 16 and 16a. Inside the envelope is a thin
layer of the gel cyanoacrylate formulation 20. To
open and use, flap 1~ and 16a are pulled apart as
shown in figure 1 and sheet 13 is torn along the
fold line 22. To facilitate substrate failure along
the side edges 14, the central outer portions of
sheets 12 and 12a may be reinforced by an additional
layer of tape or label material 23. Sheets 12 and
12a are then peeled back as shown in figure 3 to
open the package 10 and expose the cyanoacrylate gel
,0 to the air. The gel sticks to the inner surfaces
of both sheets 12 and 12a so that a maximum surface
area of cyanoacrylate mcnomer is exposed. It is
recommended that the package when opened pro~ide a
monGmer coated sur~ace area o~ at least 20 sq. in.
tl29 s~. cm.), preferably 40 sq. in. (258 sq. cm.)
or more.
Optionally package 10 may also be supplied with
a strip 24 pressure sensitive adhesive located o~
the outer surface of flap ]~a. Strip 24 is covered
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with a release paper 26 which may be pulled off when
the package is to be used. The exposed adhesive
layer 24 may then be used to adhere the open package
to a desired surface such as a wall or window.
cince the cyanoacrylate monomer is in gelled form it
does not run off sheets 1~ and 12a even when the
open package is hung vertically or upside down.
Although the seal is broken when the package is
first opened, the package may be closed after use
and reuseæ over several weeks hefore the monomer is
completely polymerized or vaporized.
Developing_The Fingerprints
For small portable evidence items a fuming
chamber such as an a~uarium fitted ~ith a lid may be
used. The lid contains a hanging device such as a
clothes har-ger or alligator clips from which the
evidence is suspended. A preferred envelope 10
contains about 3-4 grams of a gel such as in formu-
lation F in a 6 1i2" x 4" enclosure. h7hen peeled
open the surface area is approximately l3"x4". This
preferred envelope is referred to hereinafter as the
"pouch".
Items to be processed are distributed evenly
throughout the chamber. A ~ish containing warm
water is placed within the chamber. For larger
cham~ers more than one container with water may be
required. The pouch is tben peeled apart, lmmedia-
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tely placed within the chamber (at least 3 inches
fxom the items being processed), and the chamber
then sealed~ Fumec are not visible, but are present
in very high concentration within minutes.
Excellent results can be obtained using one pouch
for 20 minutes for every two and one half gallons of
chamber. The amount of time used for processing
larger chambers can be estimated using this as a
~uide (i.e., 5 gallons for 40 minutes, ten gallons
for 80 minutes with one pouch, or 40 minutes with
two pouches, etc.). Using more than one pouch is
recommended for chambers larger than twenty gallons.
Suspending the pouches from the top of the
chamber may provide bett~r results in the larger
chambers (20 gallons and larger) as the cyano-
acrylate ester molecules are heavier than air. The
addition of water to the cha~er (for humidity) is
more critical than with other methods. Water
containers should be placed so as to provide even
dispersal of the h~midity throughout the interior of
the cham~er. Overdevelopment of the prints can
occur if the processing time extends beyond twice
the time recommended aboveO Monitoring of the
processing is highly recommended.
When the fuming process is complete, caxe
should be taken when opening the chamber so as to
prevent exposure to the cyanoacrylate ester fwmes.
llpon removing the pouch from the chamber, pressing
.
of the two panels back together will stop the
release of the fumes. The pouch can be reused when
needed, often for more than ten hours of total
processing time per pouch. Once the original pGuch
seal is broken, the pouch shGu~d be used within 2
weeks, or reduced strength due to slow evaporation
may occur. The pouch should be replaced when more
than 75~ of the gel is observed to have dried.
Due to the ease of use and lack of liquid glue,
the pouch is better suited for field use than the
previously encountered methods of development. The
pouch can he used in portable chambers, automobiles,
and larger areas by using the guidelines previously
described for amount of pouches, size of chamber,
and amount of time for development. The addition of
water for humidity j E also a requirement for field
use.
Most automobiles can be processed using three
or four pouches evenly dispersed throughout the
interiar of the vehicle. Development time depends
on the siæe of the vehicle, but in ~ost cases is
2~ complete within two or three hours. ~he addition of
several beakers of warm water usually provides
sufficient humidity. Placement of the vehicle
inside on cold days and in the sun on warm days wlll
assist in lessening the effects of cold temperatures
on the processing time.
Rooms can be processed using one pouch for
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every fifteen square feet of floor space (based on
eight foot ceilinys). Examples are: 8 x 10 room =
five pouches; 12 x 12 room = lG pouches. Development
may take as long as eight hours. Water containers
should be placed so as to provide even dispersal of
the humidity throughout the room.
Suspending the pouches above and in the area
suspected of containing prints may shorten the
processing time. Addition of a small object with
test prints within the chamber is recom~,ended. The
item should be visible from the exterior of the
chamber if possible. When opening the chamber,
allow suf~icient time for the fumes to dissipate
prior to entering. Organic vapor absorbing masks or
respirators are reconnlended for entering rooms in
order tc open windows, doors, etc., for ventilation.
~he following case histories illustrating use
and comparative advantages of the inventive product
and method have been provided by the Torrence
California Police Department. The pouch used is the
pre~erred envelope descrihed above.
CASE #l
On 26 February, 1984 at approximately 0130
hours, patrol units of the Torrance, California
Policy Department were advised of a drive-hy
shootins which had just occurred in a nei~hboring
city. Units were advised that one person~had ~een
shot,
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and a description of the suspect vehicle and three
suspects within. Approximately ~ive minu~es after
the broadcast, a Torrance Police patrol unit
observed the suspect vehicle entering the city of
Torrance, from the city in which the shooting had
occurred. A subsequent stop of the vehicle resulte~
in the detention of three possible suspects. A
search of the vehicle revea]ed a Charter Arms .38
special caliber revolver with blue steel finish,
hidden in a trash container within the vehicle. The
three occupants of the vehicle were subsequently
arrested for attempt homicide.
Preliminary investiga~ion had revealed that it
was unknown which suspect had fired the shot from
the vehicle. Physica] evidence, therefore, became
critical. In addition to other evidence collected
from the suspects and the vehicle, crime scene
investigation personnel recovered the weapon. The
weapon was then transported to the Torrance Police
Department for ~rocessing, at the request of the
police agency within whose city the shooting had
occurred.
For the past several years since the intro-
duction of fu~.ing for latent prints with cyano-
acrylate esters, it had been standard operating
procedure to process most all firearms for latent
prints with the fumes from cyanoacrylate adhesive.
The process utilized at ~orrance was the use of
cotton pads treated with sodium hydroxide, to which
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three grams of the adhesive is applied. In following
these procedures, the weapon was placec' within a two
and one half gallon ac7uarium, suspended from a rod
attached to the top of the chambex. Two 2"x2"
cotton pads (pretreated) were placed within the
chamber, in addition to a small cup of water.
Approximately three grams of methyl cyanoacrylate
ester adhesive were placed on each pad, and the
chamber was sea]ed. Within five seconds the pads
were observed to commence fuming r and were observed
tG continue fuming for approximately thirty seconds.
After having been within the chamber for over
an hour, the weapon was removed and examined.
~sing normal and oblique liyht, no identifiable
latent prints were observed, and very little ridge
detail was apparent. Due to the seriousness of the
crime, it was decided to re-process the weapon with
a c~anoacrylate gel containing pouch.
The weapon was placed within the same chamher,
a~ain suspended from the top of the chamber. A
fresh cup of water was acded, and the cotton p~os
were removed. The pouch was opened and placed
within the bottom of the chamber, and the chamber
then sealed. After twenty minutes the chamber waC
opened and the weapon removed. Upcn examination of
the right side plate of the weapon, a fingerprint
was observed to he white and of value. ~everal
other latents were observed, but were determined to
be of no value. A subsec3uent comparison of the
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latent print to the inked print cards of the three
suspects rsu]ted in an identification. As the
comparisor, had been made from the ]atent still on
the weapon, atter,tion was directed to the recovery
and preservatioll of the latent. The latent was
photographed prior to processing with powder and
tape. The latent was then dusted using Lightning
black powder and a ~ephyr brush. The latent was
then li~ted a total of eighteen times. Upon
examination of the lifts, it was determined that
the fi~th lift contained the best quality ridge
detail. It w~s a~so noted that the latent on the
weapon still contained more ridc3e detail than the
lS ~est li~t.
Based on experiments with the pouch, and past
e~perience in the use of cctton pads treated with
sodium hydroxide, it is believed that the treated
cotton pads failed due tc~ the small amount of
monomer umes that were released into the atmosphere
of the ch~er. The pouch product provided maximum
evaporatiorl of the adhesive within the chamber,
thereby providin~ results where the treated cotton
2S pads ~ailed.
It has been observed that in many cases the
latent on the object that has been subjected to the
cyanoacrylate ester adhesives is of better quality
than mc~st~of the lifts obtainecl with the various
powdors and ta~es. It is strongly recommended that
latents obtained u~ing any of the various rnethods of
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applying the fumes from the adhesive be photographed
prior to application of the powder.
CA~E #2
On 04 ~ar 84 at 1400 hours patrol units of the
TGrrance Police Department were advised of an auto
theft which had just occurred within the city.
Units were advised that the vehicle was a 1976 Ford
pick-up green in color, having a green camper shell,
and of the vehicle license plate. Within 30 seconds
of the broadcast, two patrol units enroute to
another cal~ obsexved the suspect vehicle being
driven by the suspect. Units attempted to stop the
vehicle, and a pursuit ensued. As with most pursuits,
this one was brief, covering a distance of five
blocks ~here the suspect lost control of the vehic]e,
collided with a building, causing major damage. The
suspect exited the vehicle, and a foot pursuit then
ensued. The suspect was chased over a distance of
four blocks, where he was subsequently apprehended.
Although observed by two officers within the
2~ vehicle, suspect identification by latent prints in
addition to officers observations prcvides very
strong evidence. It is therefore policy to process
the vehicles in these situations for latent print
evidence. Latent lifts were obtained from the
passengers window pcint of entry, and an ashtray
removed by the suspect to gain access to the ignition
from under the dash. It was observed that the
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suspect had removed the victims ignition lock and
replaced it with an ignition lock for which the
suspect had a key. The suspects ignition lock was
recovered from the vehicle and transported to the
crime scene investigation facility for processing.
The ignition lock was placed within a two and
one half gallon aquarium containing a small cup of
water and an opened pouch. The chamber was sealed
for twenty minutes, after which the ignition lock
wa~ removed and examined. Two latent print were
observed to be white and of value. One of the
latent prints was observed or. the base of the
ignition lock, the other on the faceplate where the key
is inserted. l`he latents were photograph and then
powdered using Lightning black powder and a zephyr
brush. Six latent lifts were obtained, and again it
was noted that the latents (three lifts per latent)
on the ignition lock were of better quality than the
lifts. Comparison of the latent on the face of the
ignition loc~ to the suspect inked prints resulted
in an identification. Identifications were also
made on the lifts obtained from the window and
ashtray.
- CASE #3
On 08 Mar 83 at 0]20 hours units of the Torrance
Police Department were advised o~ a shooting that
had just occurred outside a local bar within the
city. Information received i~ndicated that four male
~uspects in a small white vehicle had driven through
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the parking lot outside the bar, and fired two shots
at a woman, hitting her both times. Units arriving
at the scene were advised by witnesses that the
occupants of the vehicle had been inside the bar
prior to the shooting. One of the suspects had
approached the victim in the bar and asked her to
dance, and was turned down. Shortly thereafter the
victim exited the bar with several friends, and was
approached in the parking lot by a small white
vehicle containing the four suspects. The victim
observed one of the suspects holding a handgun and
turned and ran, at which time two shots were heard,
the victim falling to the ground. The suspects then
fled the location in the vehicle. The victim had
received two gunshot wounds, one to the right calf,
the other to the center back, severing her spine.
Information regarding the incident was broadcast
to Torrance Police units and neighhoring agencies.
Fifteen minutes after the shooting, a patrol unit
from the Los Angeles County Sheriff's Department
observed the suspects in the vehicle mobile~ anc
with the assistance of a Torrance unit nearby
stopped the susp~cts. The suspects were placed
under arrest for attempted murder. A subsequent
search of the vehicle revealed two weapons, a
Charter Arms .357 magnum revolver with blue steel
finish, and an Enforcer pistol, .30 caliber M-l
carbine with a full 30 round magazine. The weapons
were recovered and transported to the crime scene
investigation facility for processing.
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The .357 caliber revolver was placed within ~
two and one half gallon aquarium with a small cup of
water and one opened pouch, the chamber then sealed.
Ihe Enforcer carbine was placed within a ten gallon
S aquarium with a cup of water and one opened
pouch, the chamber then sealed. After twenty
minutes the revolver waC removed from the chamber
and examined. No white latents were observed with
direct lighting. Upon examination with oklique
light, three latent prints were observed, one of
which was determined to be of value. The latent
print of value was observed on the right side plate
below the serial number. Close examination of the
weapon revealed a thin coat of oil on the surface
containing the latent. Previous experience with oil
coated surfaces had shown that application of powder
would succeed in destruction of the latent. Photo-
graphs were then obtained of the latent. A subsequent
comparison of the latent on the revolver resulted in
an identification of one of the four suspects.
The revo]ver was then properly packaged in
order to preserve the latent remaining on the
weapon. The Enforcer carbine was removed from the
chamber after forty minutes. No identifiable latent
prints were observed on the weapon. Examination of
the 30 round magazine revealed numerous latents,
two of which were determined to be of value.
Photographs were obtained of these latents, which
were ~uksequently powdered and lifted using the
previously described powder. One of the latents was
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lifted ten times, the third lift providing the best
ridge detail. It was noted that the third lift
provided better contrast than the same latent still
on the magazine. The second latent was lifted five
times. The second lift provided the best ridge
detail, It was noted that the same latent still on
the magazine ~as cf better quality than any of the
lifts ohtained from it. SubsecJuent comparison of
these patent prints to the suspects resulted in
another suspect identified.
It was further determined through physical
eviclerlce that the revolver hacJ been the weapon used
in the shooting. In addition to the other evidence
collected from the suspects and from the scene, the
suspect who had been identified to the revolver with
the latent print was determined to have fired the
weapon. The results of the physical evidence
resulted in a filing of attempt murder on this
suspect.
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