Read FBI Handbook of Crime Scene Forensics Online

Authors: Federal Bureau of Investigation

Tags: #Business & Economics, #Infrastructure, #Social Science, #General, #True Crime, #Murder

FBI Handbook of Crime Scene Forensics (3 page)

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Preserving DNA Evidence—Long-Term Storage
  • Blood/saliva (reference samples).
    • Refrigerate, do not freeze, liquid blood samples.
    • Store refrigerated, frozen (if dried), or at room temperature, away from light and humidity.
  • Blood/semen (evidence samples).
    • Store refrigerated, frozen, or at room temperature, away from light and humidity.
  • DNA tubes/tissue samples, etc.
    • Store refrigerated or frozen, if possible.
    • It is recommended that these samples be stored in a refrigerator/freezer and isolated from evidence that has not been examined.
Electronic Device Examinations
Commercial Electronic Devices

Examinations of commercial electronic devices—including personal digital assistants (PDAs), cellular telephones, pagers, and global positioning systems (GPSs)—can extract user- or owner-entered data and other information. In some cases, it is necessary to disassemble the devices during examination.

Interception-of-Communication Devices

Interception-of-communication (IOC) devices are used to unlawfully intercept oral or wire communications. The devices consist of radiofrequency transmitters and receivers. Examinations are conducted to identify operating characteristics (frequency of operation, range of operation). In some cases, it is necessary to disassemble the devices during examination.

Other Electronic Devices and Circuits

Examinations on other electronic devices and circuitry—including facsimile machines, stun guns, and bomb detonators—can extract user- or owner-entered data, stored data, and other information. The examinations can identify operating characteristics and modifications made to the devices. In some cases, it is necessary to disassemble the devices and/or circuits during examination.

Questions concerning electronic device examinations should be directed to 703-985-2400. Questions concerning shipping electronic device evidence should be directed to 703-985-1388. FBI entities may refer to the Operational Technology Division/Digital Evidence Section web page on the FBI intranet for additional information regarding evidence submission.

Follow the evidence submission directions, including
Requesting Evidence Examinations
and
Packaging and Shipping Evidence
.

  • Label the outer container “FRAGILE, SENSITIVE ELECTRONIC EQUIPMENT” and “KEEP AWAY FROM MAGNETS OR MAGNETIC FIELDS.”
  • Address the outer container as follows:

    FORENSIC PROGRAM
    BUILDING 27958A
    ENGINEERING RESEARCH FACILITY
    FEDERAL BUREAU OF INVESTIGATION
    QUANTICO VA 22135

Explosives Examinations

Evidence resulting from an apparent explosion and/or recovery of an explosive device can be examined. Examinations are based on the premise that components and accessories used to construct the devices survive the explosion, although disfigured. The examinations can accomplish the following:

  • Identify the components used to construct the device, such as switches, batteries, detonators, tapes, wires, and fusing systems.
  • Identify the explosive main charge.
  • Determine the construction characteristics.
  • Determine the manner in which the device functioned or was designed or intended to function.
  • Determine the specific assembly techniques employed by the builder(s) of the device.
  • Preserve the trace evidence potentially present in the devices so that it is not destroyed or damaged during the examinations.

Call the Laboratory at 703-632-7626 each time an explosive device or a related explosive item needs to be shipped.
The communication accompanying the evidence must reference the telephone conversation accepting the evidence.

Questions concerning explosives evidence should be directed to 703-632-7626.

Explosives are hazardous materials and must be handled only by qualified public safety personnel, military explosives ordnance diposal personnel, or erfie bomb technicians. Special packaging is required, and the amount to be shipped is regulated. An FD-861 form (Mail/Package Alert) is required for shipping bomb components to the FBI Laboratory.

Explosives Residue Examinations

Instrumental analyses of explosives residue can determine whether substances are high-explosive, low-explosive, or incendiary mixtures; whether the composition of the substances is consistent with known explosives products; and the type of explosives. Explosives residue can be deposited on metal, plastic, wood, paper, glass, cloth, and other surfaces. Residue may be deposited after handling, storing, or initiating an explosive.

Questions concerning explosives residue evidence should be directed to 703-632-7626.
Follow the evidence submission directions, including
Requesting Evidence Examinations
and
Packaging and Shipping Evidence
.

  • Some explosives residue is water-soluble and must be protected from moisture. Other residue evaporates quickly and must be collected as soon as possible in airtight containers such as metal cans, glass jars, or heat-sealed or resealable nylon or Mylar bags. Ziplock storage bags are not suitable for shipping or storing explosives residue evidence. Do not fill the containers to the top. Pack to prevent breakage.
  • Collect and preserve control samples from the blast site.
  • Extreme care must be taken to avoid contaminating explosives residue evidence
    .
  • Never store or ship explosives residue evidence with bulk explosive materials.

Never store or ship explosives residue evidence from a crime scene with evidence from a search site.

FBI Disaster Squad
  • Assists in printing the deceased at disaster scenes.
  • Assists in collecting antemortem fingerprints of victims.
  • Assists in identifying friction ridge skin of the deceased.
  • Deployment of the FBI’s Disaster Squad requires consent from the disaster scene coroner or medical examiner, a ranking law enforcement or government official, a representative of the National Transportation Safety Board, or a representative of the U.S. Department of State.
  • Requests for assistance must be made through the nearest FBI field office or the FBI’s Strategic Information and Operations Center at
    202-323-3300
    .
Feather Examinations

Feather examinations can determine bird species and can compare feathers found on clothing, vehicles, and other objects with feathers from the crime scene.

Questions concerning feather evidence should be directed to 703-632-8449.
Follow the evidence submission directions, including
Requesting Evidence Examinations
and
Packaging and Shipping Evidence
.

  • Submit feathers in heat-sealed or resealable plastic bags or paper bags.
Firearm Examinations
Firearms

Firearm examinations can determine the general condition of a firearm and whether the firearm is mechanically functional or in a condition that could contribute to an unintentional discharge. Triggerpull examinations can determine the amount of pressure necessary to release the hammer or firing pin of a firearm. Examinations can determine whether a firearm was altered to fire in the fullautomatic mode. Obliterated and/or altered firearm serial numbers sometimes can be restored. Firearms can be test-fired to obtain known specimens for comparison with evidence ammunition components, such as bullets, cartridge cases, and shotshell casings.

Comparisons of suspect firearms can be made with firearms depicted in surveillance images, possibly resulting in an “association” conclusion. Photogrammetry can determine the length of the weapon(s) used by the subject(s) depicted in the surveillance images. See
Image Analysis Examinations
.

Bullets

Fired bullets can be examined to determine general rifling characteristics such as caliber, physical features of the rifling impressions, and the manufacturer of the bullets. The microscopic characteristics on evidence bullets can be compared with test-fired bullets from a suspect firearm to determine whether the evidence bullet was fired from that firearm.

Cartridge Cases or Shotshell Casings

Cartridge-case or shotshell-casing examinations can determine the caliber or gauge, the manufacturer, and whether there are marks of value for comparison. The images of questioned cartridge cases and shotshell casings can be scanned into the National Integrated Ballistic Information Network (NIBIN) to compare with evidence from other shooting incidents. The microscopic characteristics of evidence cartridge cases and shotshell casings can be examined to determine whether they were fired from a specific firearm.

Shot Pellets, Buckshot, or Slugs

Examinations of shot pellets, buckshot, or slugs can determine the size of the shot, the gauge of the slug, and the manufacturer.

Wadding

Examinations of wadding components can determine the gauge and the manufacturer.

Unfired Cartridges or Shotshells

Examinations of unfired cartridges or shotshells can determine the caliber or gauge and whether there are marks of value for comparison. Examinations also can determine whether the ammunition was loaded in and extracted from a specific firearm. Unfired and fired cartridges or shotshells can be associated through manufacturing marks.

Gunshot Residue on Victim’s Clothing

The deposition of gunshot residue on evidence such as clothing varies with the distance from the muzzle of the firearm to the target. Patterns of gunshot residue can be duplicated using a questioned firearm-and-ammunition combination fired into test materials at known distances. These patterns serve as a basis for estimating muzzle-to-garment distances.

Gun Parts

Examinations of gun parts can determine the caliber and model of the gun from which the parts originated.

Silencers

Muzzle attachments can reduce the noise of a firearm by suppressing sound during firing. Testing can determine whether a muzzle attachment can be classified as a silencer based on a measurable sound-reduction capability.

Questions on ern n firearm ea en evidence should be directed to 703-632-8442.
Follow the evidence submission directions, including
Requesting Evidence Examinations
and
Packaging and Shipping Evidence
.

  • All firearms must be unloaded.
  • The firearm should be submitted. If the firearm cannot be submitted, call
    703-632-8442
    for instructions.
  • The firearm must be handled minimally to avoid loss or destruction of evidence. Do not allow objects to enter or contact the firearm’s barrel, chamber, or other operating surface.
  • Firearms and ammunition components such as bullets, cartridge cases, and shotshell casings can be sent via Registered Mail through the U.S. Postal Service. Evidence must be packaged separately and identified by date, time, location, collector’s name, case number, and evidence number.
  • U.S. Department of Transportation regulations and the following guidelines must be followed when
    shipping live ammunition
    :
    • Package and ship ammunition separately from firearm(s).
    • The outside of the container must be labeled “ORM-D, CARTRIDGES, SMALL ARMS.”
    • The Declaration of Dangerous Goods must include the number of package(s) and the gross weight in grams of the completed package(s).
  • Do not mark the firearm. Firearms must be identified with a tag containing the caliber, make, model, and serial number. The date, time, name(s) of the owner(s), location, collector’s name, case number, and evidence number must be on the container.
  • Do not mark bullets, cartridges and cartridge cases, shotshells and shotshell casings, or other firearm-related evidence. The date, time, location, collector’s name, case number, and evidence number must be on the container.
  • Clothing submitted for gunshot residue examination must be carefully handled, air-dried, and wrapped separately in paper. Clothing with blood must be air-dried and labeled “BIOHAZARD” on the inner and outer containers. The date, time, location, collector’s name, case number, and evidence number must be on the container.
Forensic Facial Imaging

Visual information specialists provide composite drawings, two- and three-dimensional facial reconstructions from skeletal remains, facial age progressions, postmortem reconstructions, and digital photographic manipulations and retouches. Interviews required to prepare composite drawings may be conducted either by having a visual information specialist travel to the field or by using video teleconferencing.

For facial comparisons between known and questioned subjects, see
Image Analysis Examinations
.

Questions concerning forensic facial imaging should be directed to 703-632-8194.

Glass Examinations

Glass comparison examinations can determine whether particles of glass originated from a broken source of glass. Glass fracture examinations can determine the direction and type of the breaking force and the sequencing of shots.

Questions concerning glass evidence should be directed to 703-632-8449.
Follow the evidence submission directions, including
Requesting Evidence Examinations
and
Packaging and Shipping Evidence
.

Comparison
  • Submit samples of glass from each broken window or source in leakproof containers such as film canisters or plastic pill bottles. Do not use paper or glass containers.
  • Submit samples of laminated glass (e.g., windshield) from each side of the glass. Label the samples “INSIDE” and “OUTSIDE” and package separately in leakproof containers such as film canisters or plastic pill bottles. Do not use paper or glass containers.
  • Submit the air-dried clothing of the victim(s) and suspect(s). Package each item separately in a paper bag.
  • Search for particles in the hair, skin, and wounds of the victim(s) and suspect(s). Submit particles in leakproof containers such as film canisters or plastic pill bottles. Do not use paper or glass containers.
  • Search for particles in vehicles by vacuuming each section of the vehicle separately. Do not use tape for recovering glass particles. Submit vacuum sweepings in leakproof containers. Do not use paper or glass containers.
  • Ship known and questioned debris separately to avoid contamination.
  • Do not process evidence for latent prints.
Fracture
  • Label the sides of the glass in the frame (“INSIDE” and “OUTSIDE”). Label the glass where it was removed in the frame (“TOP,” “BOTTOM,” “LEFT,” and “RIGHT”).
  • Submit all glass pieces so that the pieces can be fit together to identify the radial cracks near and at the point(s) of impact and to increase the probability of matching edges. Pack all glass separately and securely to avoid shifting and breaking during shipping.
  • Submit the entire piece of laminated glass, if possible. Secure the glass between sheets of plywood or sturdy cardboard. Do not place any objects into the impact area.

Do not process evidence for latent prints.

BOOK: FBI Handbook of Crime Scene Forensics
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