forensic ballistics gun shot residue. serial number restoration to restore a serial number that has...

Forensic BallisticsForensic Ballistics

Gun Shot ResidueGun Shot Residue

Serial Number RestorationSerial Number Restoration

To restore a serial number that has been removed or obliterated, the area must be thoroughly cleaned and polished.

Serial Number RestorationSerial Number Restoration

To restore a serial number that has been removed or obliterated, the area must be thoroughly cleaned and polished.

An etching reagent is applied which will react with the strained area faster than the unaltered metal, allowing the numbers to appear.

Collection and Preservation of Collection and Preservation of Firearm EvidenceFirearm Evidence

Firearms• Safety is the most important precaution, preventing all accidental discharge of a loaded weapon in transit.

Collection and Preservation of Collection and Preservation of Firearm EvidenceFirearm Evidence

Firearms• Safety is the most important precaution, preventing all accidental discharge of a loaded weapon in transit.• All firearm evidence should be marked for identification with evidence tag attached to the trigger guard.

Collection and Preservation of Collection and Preservation of Firearm EvidenceFirearm Evidence

Firearms• Safety is the most important precaution, preventing all accidental discharge of a loaded weapon in transit.• All firearm evidence should be marked for identification with evidence tag attached to the trigger guard.• Firearm recovered from an underwater location should be transported in the submerged in the water found to prevent rust.

AmmunitionBullets recovered at a crime scene are scribed with the investigator’s initials and should be wrapped in tissue paper before transport to protect any trace evidence.

The exact location of shell casings should be noted.

Gunpowder Deposits A firearm victim’s clothing must be preserved to prevent damage or disruption to the gunpowder residues deposited around the bullet hole.

Gunpowder Deposits A firearm victim’s clothing must be preserved to prevent damage or disruption to the gunpowder residues deposited around the bullet hole. Wet clothing should be air dried out of direct sunlight and then folded for protection.

Gunpowder Deposits A firearm victim’s clothing must be preserved to prevent damage or disruption to the gunpowder residues deposited around the bullet hole. Wet clothing should be air dried out of direct sunlight and then folded for protection. Each item should be placed in a separate paper bag.

Residue on ClothingResidue on Clothing

Clothing of the victim is chemically tested Clothing of the victim is chemically tested for gunshot residue to confirm the distance for gunshot residue to confirm the distance determination. The Griess Test indicates a determination. The Griess Test indicates a positive result with a color change to pink.positive result with a color change to pink.

Gunshot Residue (GSR) on HandsGunshot Residue (GSR) on Hands

When a weapon is When a weapon is fired residue is fired residue is propelled both propelled both forward and forward and backward.backward.

Gunshot Residue (GSR) on HandsGunshot Residue (GSR) on Hands

When a weapon is When a weapon is fired residue is fired residue is propelled both propelled both forward and forward and backward.backward.

The residue that is The residue that is propelled backwards propelled backwards leaves traces on the leaves traces on the shooter’s hands as shooter’s hands as well as anyone within well as anyone within very close range.very close range.

GSR on HandsGSR on Hands

The GSR is most The GSR is most likely concentrated on likely concentrated on the thumb web and the thumb web and the back of the firing the back of the firing hand.hand.

GSR on HandsGSR on Hands

The GSR is most The GSR is most likely concentrated on likely concentrated on the thumb web and the thumb web and the back of the firing the back of the firing hand.hand.

The GSR stays on the The GSR stays on the hands for hands for approximately 2 hours approximately 2 hours and is easily removed and is easily removed by washing or wiping by washing or wiping the hands.the hands.

GSR on HandsGSR on Hands

The GSR is most The GSR is most likely concentrated on likely concentrated on the thumb web and the thumb web and the back of the firing the back of the firing hand.hand.

The GSR stays on the The GSR stays on the hands for hands for approximately 2 hours approximately 2 hours and is easily removed and is easily removed by washing or wiping by washing or wiping the hands.the hands.

In a suicide, the In a suicide, the hands will be bagged hands will be bagged and tested for GSR at and tested for GSR at the Medical the Medical Examiner’s office.Examiner’s office.

GSR on HandsGSR on Hands

The Dermal Nitrate Test, developed in 1933, was used The Dermal Nitrate Test, developed in 1933, was used for many years. However, it gave many false positives for many years. However, it gave many false positives with cigarette ash, urine and cosmetics.with cigarette ash, urine and cosmetics.

GSR on HandsGSR on Hands

The Dermal Nitrate Test, developed in 1933, was used The Dermal Nitrate Test, developed in 1933, was used for many years. However, it gave many false positives for many years. However, it gave many false positives with cigarette ash, urine and cosmetics.with cigarette ash, urine and cosmetics.

During the test, the suspects hands were covered in During the test, the suspects hands were covered in wax. After the wax hardened it was removed and wax. After the wax hardened it was removed and chemically tested.chemically tested.

GSR on HandsGSR on Hands

The Dermal Nitrate Test, developed in 1933, was used The Dermal Nitrate Test, developed in 1933, was used for many years. However, it gave many false positives for many years. However, it gave many false positives with cigarette ash, urine and cosmetics.with cigarette ash, urine and cosmetics.

During the test, the suspects hands were covered in During the test, the suspects hands were covered in wax. After the wax hardened it was removed and wax. After the wax hardened it was removed and chemically tested.chemically tested.

A blue color indicated a positive result for GSR.A blue color indicated a positive result for GSR.

Today’s tests for GSR on HandsToday’s tests for GSR on Hands Barium and Antimony are both components in Barium and Antimony are both components in

GSR. Several techniques are used to test for GSR. Several techniques are used to test for these elements.these elements.

Today’s tests for GSR on HandsToday’s tests for GSR on Hands Barium and Antimony are both components in Barium and Antimony are both components in

GSR. Several techniques are used to test for GSR. Several techniques are used to test for these elements.these elements.

1.1. First, the investigator will remove the GSR First, the investigator will remove the GSR particles with tape or swabs.particles with tape or swabs.

Today’s tests for GSR on HandsToday’s tests for GSR on Hands Barium and Antimony are both components in Barium and Antimony are both components in

GSR. Several techniques are used to test for GSR. Several techniques are used to test for these elements.these elements.

1.1. First, the investigator will remove the GSR First, the investigator will remove the GSR particles with tape or swabs.particles with tape or swabs.

2.2. Next, the particles may be examined with a Next, the particles may be examined with a Scanning Electron Microscope, Neutron Scanning Electron Microscope, Neutron Activation Analysis or Flameless Atomic Activation Analysis or Flameless Atomic Absorption Spectrophotometry.Absorption Spectrophotometry.

Today’s tests for GSR on HandsToday’s tests for GSR on Hands Barium and Antimony are both components in Barium and Antimony are both components in

GSR. Several techniques are used to test for GSR. Several techniques are used to test for these elements.these elements.

1.1. First, the investigator will remove the GSR First, the investigator will remove the GSR particles with tape or swabs.particles with tape or swabs.

2.2. Next, the particles may be examined with a Next, the particles may be examined with a Scanning Electron Microscope, Neutron Scanning Electron Microscope, Neutron Activation Analysis or Flameless Atomic Activation Analysis or Flameless Atomic Absorption Spectrophotometry.Absorption Spectrophotometry.

3.3. The presence of Barium and Antimony is The presence of Barium and Antimony is considered a positive for GSR.considered a positive for GSR.

Serial Number RestorationSerial Number Restoration Firearms are “ stamped” Firearms are “ stamped”

with an identification with an identification serial number. These serial number. These numbers are linked to the numbers are linked to the buyer of the firearm.buyer of the firearm.

Serial Number RestorationSerial Number Restoration Firearms are “ stamped” Firearms are “ stamped”

with an identification with an identification serial number. These serial number. These numbers are linked to the numbers are linked to the buyer of the firearm.buyer of the firearm.

Identification numbers are Identification numbers are usually etched on the usually etched on the metal body, frame or metal body, frame or plate of the gun.plate of the gun.

Serial Number RestorationSerial Number Restoration Firearms are “ stamped” Firearms are “ stamped”

with an identification serial with an identification serial number. These numbers number. These numbers are linked to the buyer of are linked to the buyer of the firearm.the firearm.

Identification numbers are Identification numbers are usually etched on the usually etched on the metal body, frame or plate metal body, frame or plate of the gun.of the gun.

Many times, criminals Many times, criminals “erase” the serial number “erase” the serial number and it has to be restored and it has to be restored once the weapon is at the once the weapon is at the crime lab.crime lab.

Distance DeterminationDistance Determination

Distance determination is necessary for Distance determination is necessary for many gunshot wounds. If the shooter many gunshot wounds. If the shooter pleads self-defense, it is very important to pleads self-defense, it is very important to know the distance between the shooter know the distance between the shooter and victim.and victim.

Distance DeterminationDistance Determination

Distance determination is necessary for Distance determination is necessary for many gunshot wounds. If the shooter many gunshot wounds. If the shooter pleads self-defense, it is very important to pleads self-defense, it is very important to know the distance between the shooter know the distance between the shooter and victim.and victim.

Suicide victims will also have residue on Suicide victims will also have residue on close wounds. Lack of residue may close wounds. Lack of residue may indicate foul play.indicate foul play.