Introducing Shooting Scene
Investigations
Shooting incidents
In the tabloids with spectacular headlines almost daily.
Movie Classics:
Film Noir or Gangsters
 Capone gang spraying bullets inside
the SMC Cartage Company garage on
Valentine’s Day in 1929 or
 Eliot Ness’ band of Prohibition
Bureau Agents peppering kegs in one of
Capone’s breweries,
Modern society provides a
different image
 The troubled Virginia Tech student
who shoots-up a campus classroom
killing multiple innocents,
 Army Major Nidal Malik Hasan who
murdered his fellow soldiers at Fort Hood.
 Shooting in Aurora CO Movie Theater
 Newtown, CT massacre of first
graders by Adam Lanza
Shooting Incidents
Change the Investigative Equation
The presence of firearms evidence creates a new set of
investigative challenges, such as the additional the fragile
evidence discussed above.
Sexual assault cases
 Mandate a search for biological and trace evidence.
 If case also involves a shooting … scene complexity ramps
up.
 If it also involves a vehicle, the scene complexity ramps up yet
again because bullets do weird things inside vehicles.
Types of Shooting Scenes
Accidental discharge of a weapon
Accident – hunting incidents
Suicide
Homicide
Drive-by shootings
Terrorist activity
Emotionally disturbed incidents
Who Investigates Shooting Scenes?
 Qualifications of shooting scene investigators
 Do not need to
 Firearms experts,
 Experts in forensic ballistics,
 Perform bullet matches
 Muzzle-to-target experiments
 Need to understand the principles involving shooting
incident scenes
 Ask appropriate investigative questions
o Investigators consider what happened and its
implications.
 Should be experienced scene investigators
 Have thorough knowledge and understanding of how to
conduct a comprehensive scene investigation.
 Know how to investigate shooting scenes
What is the Thought Process?
 Logic Rules
 For example: Ricochet - what should it look like?
 An experienced-based question
 Knowing what to expect can lead to finding firearms related
evidence,
o Such as an original impact site or defect, the terminus, the
bullet, the victim’s wounds and/or clothing.
 Concentrate on what is known
 Damage to the recovered projectiles,
 Wound characteristics,
 Bullet hole/ricochet characteristics (size, chemistry, trace evidence)
 How do these relate to the overall scene characteristics and
what happened.
 Information in dispute, such as the specifics of the event, but … should
not be prime consideration at first. Many questions will be answered later.
 The ME will answer other questions concerning the origin and distance
of possible stippling or fouling on a victim’s skin.
On-Scene Considerations
Information Sought
 Number & ID of individuals involved – shooters and nonshooters
 Position of shooters
 Witnesses and their relative locations and sight lines
 Obtain witness accounts of shots fired.
 Lighting/weather conditions
 Bullet/defect identification and chemical analysis
 Bullet flight path(s) angular component determinations
 Location and type of trace evidence
 ID of artifacts created by EMTs, witnesses, investigators
 Collection of fragile evidence
 Ancillary determinations
 Muzzle-to-target distances, if necessary.
 GSR analysis
On-Scene Considerations
Information Sought
 Categorize all bullets from all weapons, at the scene
or from recovered weapons.
 Determine the number of missing bullets from all
weapons
 Locate, all identifiable bullet holes
 Entry versus exit
 Ricochet marks
 Deflections
 Other firearms related defects
 Identify the number and types of wounds
First Consideration
Fragile Evidence
GSR - Gunshot residue
 Gunshot residue: Anything that might contain GSR must be located
expeditiously, collected and preserved properly.
 The list of places where GSR might be found depends on the specific
investigation
 hands and clothing of victims and shooters,
 bullets,
 ricochet defects and
 bullet holes. First Consideration: Fragile Evidence
 Collecting evidence for GSR.
 The general procedure requires carefully folding clothing, much as for
preserving bloodstain evidence, in order to avoid inappropriate transfer
from one to another.
 Protecting areas where GSR might have fallen or was deposited, such as
pockets, arms, the place where a shooter stood.
Fragile Evidence
 The usual fragile evidence:
 Footprints, tire tracks, fingerprints, etc.
 Bullets
 Deformation to ascertain angle of impact and strike surface
characteristics
 Fragmentation and fragment locations
 Rifling & twist to help identify specific weapons
 Number of lands and grooves visible
 Adherent trace evidence
Bullet/projectile marks and holes.
 Little danger of the bullets themselves being ruined …
 Source of important microscene elements,
 Blood
Fragile Evidence
Cartridge cases:
 Pinpoint the area from which a weapon had been
discharged
 Contain marks that can have diagnostic value
 Protect from further damage
 Pattern formed by ejected cartridge
o Category of fragile evidence because
cartridge cases are easily moved – kicked, etc.
o Patterns or cartridge case scatter must be
archived photographically.
Fragile Evidence
Bullet Defects/holes & Trace evidence
 Bullet Marks have important microscene elements,
 Think about preservation
 Devise a strategy
 Blindly performing tests on a bullet holes can ruin the
trace evidence present.
o The sequence of testing must be considered
carefully, chemical analysis is LAST.
 First … document the defect.
 Second … Preserve trace evidence present.
 Tape lift trace evidence
 Cast the defect/hole using silicone casting material.
The casting material captures the trace evidence and
forms a mold of the defect.
Basic Facts
Definitions and Terms
The Language of Shooting Scenes
and Forensic Ballistics
Small arms ammunition
 From a forensic perspective, small
arms ammunition consists of a
cartridge case, primer, propellant and
a bullet.
 Essentially, there are three
common types that are manufactured:
 Rimfire,
 Center fire
 Caseless.
Ammunition
http://ingunowners.com/forums/long_guns/86953-i_found_a_handy_little_rifle_ammo_size_reference_chart.html
http://ingunowners.com/forums/handguns/86824-i_found_a_handy_little_handgun_ammo_size_reference_chart.html
Caliber Travel Distances
http://www.google.com/imgres?imgurl=http://www.hookertactical.com/image
s/Ballistic%2520Chart.PNG&imgrefurl=http:
General Anatomy of Bullets
Small arms ammunition
Term
Description and/or Definition
Primer
The mechanism for igniting the propellant.
1. Rimfire ammunition: firing pin crushes a soft hollow rim of the cartridge to explode
the primer.
2. Center fire ammunition: Primer held in a cup in the base of the cartridge. Primer
crushed by firing pin.
Propellant
A mixture of chemicals that must be ignited from a primer. Ignited propellant produces
gases that propel the bullet down the barrel of the firearm.
Cartridge Case
1. Straight cased
2. Bottle-necked
3. Tapered case
A holder for the propellant and primer … not the bullet.
1. Diameter is constant along length
2. Long case narrows to hold the bullet
3. Old European style: Wide-based case gradually reduced.
1. Bullet
2. Pellets
3. Shot
1. A missile that is either fired or unfired.
2. Individual lead or steel balls for shotgun ammunition
3. Another term for pellets, e.g., ‘lead shot.’
Rimfire
ammunition
Short brass, generally 0.22in in diameter. Closed end is flat head with a hollow rim with
primer. Firing pin strikes rim which crushes and explodes primer. The resulting flame
ignites propellant.
Center fire
ammunition
Brass, the head is thick and heavy with a central recess or pocket for primer cap. A hole
goes from the primer pocket to cartridge, allowing flash to reach the propellant.
Caseless
ammunition
The propellant surrounds the bullet as a single, solid piece. No cartridge. The primer is
usually at the rear of the propellant. Not typically associated with shooting incident scenes.
 Bore or gauge,
 Number of lead balls of the same diameter as
the inside of the barrel that weighs 1 lb.
 Thus, a 12 gauge shotgun has a barrel of
0.729 inches and 12 round balls 0.729 inches
in diameter that weigh 1 lb. Unlike rifled
weapons, shotguns have a smooth barrel that
fires pellets, a single ball or dust shot ).
 Shotgun pellets
Traditionally composed of lead and a small
amount of antimony.
 Other materials also include: soft steel with a
copper coating and bismuth alloyed with iron
and/or tungsten.
 Single projectiles used in shotguns are called
slugs, which can be round balls, also known as
pumpkin shot.
Specialized single projectile rounds
o Police ammunition called Hatton
rounds (also known a breaching round –
designed to shatter deadbolts, door
locks and hinges and tear gas rounds.
 Type of shot depends on its shape.
 Examples include Brenneke, Foster or
Sabot slugs.
Shotgun
Ammunition
Shot Shell Sizes
No. of lead balls
in one pound
10
12
16
20
28
http://en.wikipedia.org/wiki/Shotgun_shell
Diameter of
requisite pure lead ball
0.78" (19.7 mm)
0.73" (18.5 mm)
0.66" (16.8 mm)
0.62" (15.6 mm)
0.55" (14.0 mm)
Shotgun Pattern Testing
 Actually a muzzle-to-target
distance determination.
 Requires examining for the
pattern of holes created by the
shotgun pellets.
 The "unknown" pattern is
compared to "test" patterns
created using suspect shotgun
fired at known distances.
 Allows for an approximate
muzzle-to-target distance to
be determined.
http://www.firearmsid.com/A_distshotpatt.htm
Primer Compounds
 Priming compounds are a shock-sensitive mixture of chemicals …
explode when struck by an object … a firing pin.
 Resulting debris is known as primer powder residue or gunshot
residue (GSR).
A possible concern is ammunition in a fire
 Primer compounds in the ammunition are heat and shock sensitive.
 Temperatures ranging from 190-260oC can cause spontaneous
combustion which can ignite the propellant.
o Possibility of accidental discharge of bullets in fires is slim.
The soft brass of the cartridge case relaxes grip on the
bullet
 Prevents a build-up of pressure. Nevertheless, in any
fire, this should be a concern.
Lead-based Primers
 Until 2000, the most common components of priming compound were lead
based.
 Typically included explosive ingredients (lead styphenate and tetrazine), an
oxidizer (barium nitrate) and a fuel to promote burning (antimony sulfide).
 Powdered glass was added to increase friction and to assist in the
detonation.
 Aluminum and magnesium were added to high powered magnum
pistols or rifles.
Lead-free and non-toxic Primers
 Replace poisonous lead in primers with lead-free equivalents.
 Explosive component chemicals such as dinitrodihydroydiazoenzene salt
(diazinate), dinitrobenzofuroxan salts, potassium dinitrobenzofuroxan,
perchorate or nitrate salts, diazo, trizole and tetrazaole compounds and
others.
 New oxidizers include zinc oxide, potassium nitrate, strontium nitrate, zinc
peroxide, and the fuel components might include boron, metallic powders,
carbon, silicon and metal sulfides.
Bullet Terminology
Type of Bullet
Description
Wadcutter
Flat nosed with a sharp shoulder. Designed to produce clear holes in paper
targets
Spitzer
German term applied to an elongated ogival bullet with a sharp point.
Soft point or semijacketed
A jacketed bullet with the jacket cut back to reveal a lead core
Hollow point
Usually semi-jacketed with a cavity, which expands on impact with soft
targets. This increases the wounding effect of the bullet.
Dum-dum
0.303” rifle bullet. The Mark II version is fully jacketed. Outlawed by the
Hague Convention for military use but not for police use. Often
mislabeled as a hollow point.
Rifled slug
Lead (steel & lead or plain steel) for smooth bore shotguns. Designed for
hunting, it is also used by police. Outside of slug has helical ribs.
Saboted bullet
Sub-caliber, plastic coated bullet. Attains high velocities because of smaller
diameter. Plastic shed when bullet leaves the barrel.
Flechette
Thin nail-like projectile stabilized by fins. Designed for military in the 1950s
but was inaccurate.
Forensic Ballistics
 The analysis of bullets and
bullet impacts to determine
information concerning
usefulness to the legal system.
Separately from ballistics
information, firearm and tool
mark examinations
 Analyzing firearm,
ammunition, and tool mark
evidence to establish
whether a certain firearm or
tool was used in the
commission of a crime.
http://upload.wikimedia.org/wikipedia/commons/2/23/Bullet_coming_from_S%26W.jpg
Internal or Interior Ballistics
 Study of what happens in the
barrel of a weapon,
 What happens when the
firing pin strikes the primer to
when the bullet or projectile
exits the barrel of the
weapon.
 Topics interest:
 Primer ignition, barrel
pressures, velocity, time the
bullet remains in the barrel,
recoil, etc.
What happens here determines what
the bullet leaves on a defect
Transitional Ballistics
Transitional Ballistics
 What happens in
the GSR cloud
External Ballistics
Study of bullet flight after it leaves
the muzzle,
 Also known as the bullet path or
incorrectly the trajectory.
 For most shootings, distances are
short, which means the maximum
range of the firearm is not a serious
consideration.
 However, depending on the
scene, long distance shots could
become a part of the investigation.
In these instances, appropriate
expertise should be sought.
 The subject is complex involving
calculations that include bullet shape,
sectional density, atmospheric
pressure and possibly the rotation of
the earth.
Terminal Ballistics
What happens when bullet
interact with targets.
 Wounds to people
 Interaction with inanimate
objects such as water, soil,
concrete, wood, and other
materials.
Bullets & Bullet Defects
- Locard’s Principle In Action -
Language of Bullet Defects
Bullets, Projectiles & Defects (Marks)
Definition
Target
Terminus or “final target”
Intermediary target
An object struck by a projectile
The place where a bullet stops
Object struck by bullet on way to terminus.
Defects
a. Bullet Impact Marks (BIM’s)
b. May or may not be aligned to a bullet’s path to its
terminus.
Bullet marks
a. Deflection defect: Bullet grazes a target
b. Skip or skid: Bullet leaves a brief shallow mark
c. Furrow or trench: Bullet leaves longer deeper mark
d. Chunk-out: Piece of target knocked out
Secondary projectile
Piece of target dislodged and becomes a projectile
Secondary projectile defect
Sympathetic fracture
Bullets
Secondary projectile leaves a mark on an object
Occurs not directly from the bullet impact.
a. Intact: Bulled recovered whole
b. Deformed: Shape is altered because of hitting the final
or intermediate targets
c. Bullet or jacket fragment: Ppiece of the bullet
resulting from contact with a target.
d. Metallic fragment: Possible bullet fragment that is
not readily identifiable
Additional Terminology of Bullet Strikes
Bullets strike targets in various ways, and like bullets and its defects, these have a language of
their own. The on-scene identification of which holes/defects result from a bullet strike is important
because, if misinterpreted, the investigation can result in an incorrect and flawed reconstruction of
the incident’s events.
Common Bullet Mark Terminology Illustrated
Term
Meaning
Perforation
Bullet enters & exits
target
Penetration
Bullet enters target but
does not exit
Imbed
Bullet just enters target
but is not completely
inside
Spall
Bullet enters target and
punches debris on exit
side without exiting
Deflection
Bullet hits target and then
changes direction, not
entering target
Illustration
Bullet Path
Spalling
Bullets Have Important
Forensic Investigative Information
 Bullets have an incredible amount of
forensic information.
 Bullet Holes - Caliber (an approximation)
and ammunition type
 Bullet flight path – What it hit on its journey
 Bullet Path Component Angles
 Position of the shooter
 Bullet strike surface characteristics
 Ricochet(s)/defect interpretation
Bullet Holes and Other Defects
Forensic Investigative Information
 Bullets/Holes have forensically important physical evidence.
 A bullet can interact with multiple targets,
 Collects parts of what it hits and leaves physical
material
 Micro-traces (Locard Elements) such as elements from the
barrel of the weapon and from the primer discharge.
 When bullet exits GSR cloud, it leaves these
microscene elements (trace evidence) in the hole/defect it
creates after hitting an object as well as part of the bullet
itself.
o Tell investigator what the gun was and who and/or
what it struck along the way.
 The astute/competent investigator
 Carefully examine recovered bullets visually, if for no
other reason than to see what is on its surface
Identifying a Bullet Hole
Bullet Wipe
“Mixture of bullet lubricant, mouth sealant and carbonaceous material
picked up by the bullet whilst traveling down the bore, which is deposited
on any material through which it passes.”
Material on Bullet Surface is Deposited on a Struck Surface (Defect)
 In the Barrel:

A bullet travels down the barrel of a gun, its surface becomes contaminated with
material from previous discharges of the weapon, some of which is carbonaceous material
and condensed GSR.
 Leaving the Barrel:

Flies though cloud of rapidly condensing GSR … deposits onto bullet. Bullet leaves
GSR cloud … strike a target … deposits surface contamination and part of its metallic
content.

Material transferred from the bullet to defect … important to visually check defect …
“feel” for what is there. If bullet deposit – bullet wipe – is present, there is a good chance
the hole/defect was made by a bullet.
Identifying Bullet wipe?
First Visual Test:
Examine the Defect
 Black or gray ring around the
hole is diagnostic for bullet wipe.

The larger the ring, the
more carbonaceous material
was present on the bullet.
 Testing should not cease
after a visual inspection.
 Suspecting a hole/defect
is from a bullet is when the
analytical phase begins.
http://www.fbi.gov/about-us/lab/forensic-science-communications/fsc/april2004/images/research2_08.jpg&imgrefurl=http://www.fbi.gov/aboutus/lab/forensic-sciencecommunications/fsc/april2004/index.htm/research/2004_02_research02.htm&h=268&w=400&sz=11&tbnid=UeNfY6JdmpY3SM:&tbnh=90&tbnw=134
&prev=/search%3Fq%3DBullet%2Bwipe%26tbm%3Disch%26tbo%3Du&zoom=1&q=Bullet+wipe&usg=__9IS7spj1jbkY_jv8UoMwMF6PI6w=&docid=
BTOUmmH3j2N-PM&hl=en&sa=X&ei=SoOzUJjYHcm40QGA3IHACw&ved=0CEoQ9QEwBg&dur=601
Trace Evidence
Second Visual Test
 Use a hand-held magnifying glass and/or a 40X microscope to
search for trace evidence: fibers, fragments of metal from the
bullet’s travel down the barrel, debris from other intermediate
targets, and blood.
Third Test - Chemistry
 Chemical spot tests Help identify composition of the bullet.
This completes the on-scene analysis.
 Note: remove trace evidence in the hole/defect by tape
lifting or casting.
 While this might also remove some of the bullet wipe
and could (probably not) compromise chemical testing to
identify the composition of the striking projectile.
Revolver Firing
Lead
Copper
Nickel
Gunshot Residue – GSR
Primer Powder Residue
Lead
Barium
Antimony
Testing for Lead
 After the explosion of the primer powder and ignition of the propellant, the
cartridge releases the bullet allowing it to travel the length of the barrel where it exits
and flies through a cloud of volatilized primer powder - GSR - containing vaporized
lead, antimony and barium (depending on the composition of the primer).
 A small portion of vapor quickly condenses onto the surface of the bullet
 Finding lead around a suspect hole or defect in a wall or through clothing,
while presumptively positive for lead is also presumptively positive for a bullet
strike.
 A common presumptive test for lead takes advantage of the reaction of sodium
rhodizonate with lead.
 The sodium rhodizonate reaction is results in a lead-rhodizonate complex that
is a deep purple/pink color,
 The test is simple to perform and gives nearly instantaneous results.
 Barium and antimony give a similar test, but a positive rhodizonate test
for lead is a reddish-purple-pink color that turns blue/purple after spraying
with a solution of 5% HCl.
On-Scene Lead Testing
Procedure
 Press a dilute acetic acid moistened swab or
piece of gauze against a surface to be tested – a
suspected bullet hole on metal or a wall or on clothing.
 Check for color formation. If there is no color
change,
 Place a drop of the aqueous sodium rhodizonate
(dilute solution in dilute acetic acid) onto the swab.
 If the swab or gauze turns a bright reddish-purple,
the test is positive. A positive test means that it is likely
– not confirmed – that lead is present, which is
consistent with the presence of a bullet hole.
Alternate Procedure for
Larger Surfaces
 Moisten a piece of filter paper in tartrate solution
and press it against a suspected bullet impact mark
(BIM) for several seconds.
 Remove the paper and spray it with a dilute
solution of sodium rhodizonate.
 A reddish-purple/pink color is a positive test.
Positive Rhodizonate
Test for GSR (Lead)
Test for Lead
Sodium rhodizonate for Pb
• Tested directly on the object or lift
– 15% acetic acid (or 2.8M Tartrate) solution of sodium
rhodizonate
• Prepared fresh
• Overspray with 5%HCl
– Differentiates Pb from Ba and Sr, which give similar color
– Pb will turn blue/purple after 5% HCl spray
Sodium Rhodizonate
15% Acetic Acid
Pb-conjugate –
Pink-Purple/blue In Acid Solution
The Bashinski Transfer
Position the area to be tested.
Place a piece of laboratory filter paper over the test area.
Place a test mark on the filter paper.
Index the filter paper in pencil relative to the test item indicating the location of suspected bullet
holes, seams, buttons, button holes, pockets, rips, tears, etc., for future reference.
Prepare the filter paper.
Dampen the filter paper uniformly while positioned on the test item by spraying with a 15 percent
solution of glacial acetic acid in distilled or deionized water.
Lift residues from item.
Cover the dampened filter paper with several layers of dry filter paper and apply heat with an iron
until the paper is dry.
Perform color test.
Remove the original filter paper from direct contact with the test item.
Spray the filter paper with the saturated solution of sodium rhodizonate.
Spray the filter paper with the buffer solution.
This solution eliminates the yellow background color caused by the sodium rhodizonate,
establishes a pH of 2.8, and displays a pink color in the presence of lead and some other
heavy metals.
Spray the filter paper with the hydrochloric acid solution.
The pink color fades leaving a blue-violet color, indicating the presence of lead. Note that
positive blue-violet indications are a mirror image of the deposition on the test item.
Label and retain test paper.
Mark the previous pencil marks placed on the test paper in ink when the paper is dry. Label with
additional data according to laboratory protocol. This result can fade quickly; observations should
be photographed and documented promptly
Lead Splash
 Sometimes a lead bullet will disintegrate after a low impact
angle strike,
 Vaporized lead occurs from force of the impact and
friction.
 Vaporized the lead quickly condenses back onto the
surface in a pattern showing the direction of the impact.
 Condensed lead is known as ‘lead splash’ and it flows
in the direction the projectile was moving. It is not always
visible until treated with rhodizonate
 Often a gray defect is on the surface
 Cannot be labeled as a bullet impact mark or strike until
after obtaining a positive sodium rhodizonate test.
Lead Splash
Plain lead .22
Long Rifle bullet
Thick Al plate
Sodium Rhodizonate Lift
Ricochet
Mark?
Lucien C. Haag
Shooting Incident Reconstruction
Elsevier, 2006, pg 43
Further Chemical Characterization of Defect
Identifying Jacketed Bullets
 Bullet-hole chemistry does not stop with the rhodizonate
lead test because bullets are not always lead-only projectiles.
In fact, many are jacketed with copper or nickel, the former the
more prevalent.
 By identifying the presence of either copper of nickel as a
component of the bullet wipe, more information about the bullet
can be determined.
 Knowing whether the bullet defect was caused by a
jacketed bullet can help narrow the choices among bullets
that could have caused the defect,
 Especially if some shooters are using copper
jacketed ammunition and others not.
Testing for Copper Jacketing
Analyzing Metallic Trace of Bullet’s Surface




Unjacketed = Lead
Jacketed = Copper or Nickel.
If copper, traces should be detectable,
Two tests for Copper
 One test, the DTO test reagent is made from Rubeanic Acid
(Dithiooxamide) which complexes with copper to yield a mossygreen/charcoal color.
 Performing is almost identical to lead except that the
reagents are different.
 The DTO test for copper uses a 0.2% w/v ethanolic solution
in dilute base - ammonium hydroxide. Although the test is more
sensitive than the sodium rhodizonate test for lead, when lead
splash is present, the lead can mask the copper which, in terms
of the amount present, will not be as prevalent.
Testing for Copper
 Hardness of Copper vs Lead
 Copper is a much harder metal than lead (Mohr
hardness of 1.5 for lead vs. 2.8 for copper).
 Means copper is less likely to leave a deposit than
lead.
 DTO test is more sensitive than the sodium
rhodizonate test for lead, there is less copper present.
 Second test for Copper = 2-nitroso-4-naphthol (2-NN) as
color producing reagent.
 The 2-NN complexes with copper to give a light pink
color. It also reacts with iron and zinc to form green and
orange colors respectively.
 Investigators do not have to choose which test to use
can be performed sequentially.
Testing for Copper
DTO – Dithiooxamide (Rubeanic acid)
• Test for copper
Two Chemical
Tests for Copper
– Mildly basic solution (NH4OH)
– More sensitive than Sodium rhodizonate test for lead
• Sensitivity compromised by
– Hardness & higher boiling point of Cu versus lead
– Ability of exposed lead to overwrite underlying Cu
– Color produced can be difficult to see
• Always assume both lead & copper present
– DTO test done before rhodizonate test
• Mild acidic soln. used to transfer Pb residues also transfer copper
• Pb test removes the copper
– No such thing as copper splash
Dithiooximide
Ammonium Hydroxide
Dark Mossy Green-charcoal
Testing for Copper
2-NN: 2-nitroso-1-naphthol
• Test For Copper
– 2NN - Gives pink color
• Easier to see against dingy backgrounds
– False positives eliminated by drying “lift” & over-spraying with DTO
– Used like DTO test
– DTO and 2-NN Tests can be done in sequence, with the 2-NN
test first.
2-Nitroso-1-Naphthol
+++
Fe
++
Cu
Green
Pink
Zn++
Orange
Sequential Testing for Pb & Cu
NH4OH
C u + Pb
Pb
Retained
+Cu-DTO Complex
Mossy Green
DTO
Bullet hole – BIM or Defect
Acetic
Sodium
Acid rhodizonate
Lead
Rhodizonate
Pb-Rhodizonate Complex
Pink/purple Color
Testing for Nickel
Dimethylglyoxime (DMG) test for Ni
• Nickel Jacketed Ammunition has shiny mirror-like sheen
– Properties of Nickel (Ni)
• At. Wt.: 58.71
• Melting point: 1555 Deg C.
• Nickel is a hard Metal (Mohr hardness)
– Steel (4.0)>Ni (3.8)>Cu(2.5)>Pb(1.5)
– Ni resists oxidation
Dimethylglyoxime
Scarlet-Pink Precipitate
– Forms insoluble (red) salt with
nickel salts
– Test useful for barrels of guns
that shoot Ni ammunition
• Ni plated bullets are
relatively uncommon
• One round of Ni-plated
bullet will leave Ni deposit
in barrel
• Use 2:5 NH4OH to swab the
barrel.
Bullet Holes and Caliber
Caliber defined,
 “A numerical value, included in the cartridge name, to indicate
the approximate diameter of the missile.”
And also,
 “The diameter of a projectile, commonly expressed in
hundredths or thousandths of an inch in the United States, when
discussing small arms, although it may also be expressed in
metric units. Caliber may also refer to bore or groove diameter,
again, in either inches or millimeters. A term also used to
designate the specific cartridge(s) for which a firearm is
chambered. May be used as a unit of measure. For example, a
bullet can be described as three calibers in length, when its length
is three times its diameter.”
Comparison between two bullet holes test kits : Plumtesmo/Cuprotesmo and BTK
Author: M Petit
Co-author(s): J Le Roy, T Berthail, S Helstroffer
Organization: Institut de Recherche Criminelle de la Gendarmerie Nationale
Country: France
Presenter: M Petit
Theme: Scene of Crime
Bullet holes and bullet impact strike marks are often very hard to identify directly on crime scene by
investigators. Some colorimetric test kits now exist to detect lead or copper residue and can be directly
used on the field to support the hypothesis of a bullet hole or not. Two different kits for lead residues
detection, Plumbtesmo® and BTK lead, and two for copper residues detection, Cuprotesmo® and BTK
copper, have been tested in this study with different types of ammunitions and target surfaces. Results
demonstrated that BTK is slightlty more efficient than Plumbtesmo® for lead residues detection, and
much more powerful for copper residues than Cuprotesmo®. BTK and Plumtesmo®/Cuprotesmo®
possess all the advantages needed for field investigation (quick, easy to use, safe, non toxic, small,
lightweight, compact and immediate response) but BTK results are more contrasted and are easier to
observe. BTK seems to be a very efficient field test for bullet hole and ricochet marks detection.
References:
] L.C. Haag, 2006, Shooting Incident Reconstruction, Elsevier Academic Press, Burligton, pp. 45-56.
J. Jacobson, J.M. Swanepoel, K.S. Wong, 2010, Evaluation of Plumbtesmo® and Cuprotesmo® Test Paper
for Sensitivity to Lead and Copper Residues, AFTE Journal, Vol. 42, pp. 49-55
M. Steinberg, Y. Leist, M. Tassa, 1984, A new field kit for bullet hole identification, Journal of Forensic
Sciences, Vol 29, pp.169-176
Bullet Holes and Caliber
Skin
 Elastic … caliber determination nearly impossible.
 After passing through, skin attempts to regain its original shape.
 For round-nosed and hollow-point bullets, the hole diameter is much
smaller than the bullet caliber.
The bullet wipe diameter, too, will be smaller.
Fabrics
 Fabric bullet holes are smaller than the caliber.
 Only diagnostic information is from torn fibers, which can indicate the
direction of travel.
Wood
 Can be approximated by placing a piece of strong, white paper over the
wood surrounding the hole.
 Rubbing the surface over the hole with a lead pencil
 White circle approximates caliber – the diameter of the bullet.
Vehicle tires
 Are almost self-healing, determining the caliber of the bullet is impossible.
Vehicle body metal
 Semi-jacketed hollow-point bullets can leave a large entry hole
 If stripped of its jacket, these same bullets can leave a smaller hole
 High velocity bullets can leave larger holes making the entrance seem
more like an exit hole.
Bullet Holes and Caliber
 Velocity of the bullet
 How bullet made.
Sheet metal … important because of large number of vehicular
shootings. A full metal jacketed bullet interacts with sheet metal and deforms
it depending on the impact velocity.
 Low Impact velocity: Leaves holes smaller than the
diameter of the bullet
 Metal is slightly elastic
o At low bullet velocities, the metal relaxes
(contracts) and has time to relax and deform.
 Higher velocities: Hole becomes progressively larger,
eventually larger than diameter of bullet.
. At higher velocities the metal expands and has little time to
stretch, which results in less deformation.
 Lead and alloy bullets produce larger holes than the bullet diameter.
 Softer lead expands on contact before the metal can deform.
Trace Evidence and Bullet Holes
Fragile Evidence
 Bullet leaves the barrel … travels to its terminus … strike a number of
intermediate targets …. surfaces made from different materials – glass,
plaster, skin, fabric, anything.
 If Locard’s Exchange Principle holds true - energy is needed to
create a fracture (Principle of Divisible Matter) - bullet’s surface
should reflect its journey.
 Red, plaid shirt … fibers could be imbedded on the ogive
(nose
 Tempered glass, it might have a scored surface from the sharp
edges of the already fractured glass.
 Human tissue, blood should be present. A bullet passing
through the head of an individual might have adherent blood, hair
and/or bone particles.
 Evidence adhering to a bullet is fragile evidence and it must be treated
as such … handling carefully to preserve fragile trace evidence is present