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 (8 page)

BOOK: FBI Handbook of Crime Scene Forensics
5.51Mb size Format: txt, pdf, ePub
ads
Soil Examinations

Soil examinations can determine whether soils share a common origin by comparing color, texture, and composition.

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

  • Collect soil samples as soon as possible, because the soil at the crime scene can change dramatically.
  • Collect soil samples from the immediate crime scene area and from the logical access and escape route(s).
  • Collect soil samples where there are noticeable changes in color, texture, and composition.
  • Collect soil samples at a depth that is consistent with the depth from which the questioned soil may have originated.
  • If possible, collect soil samples from alibi areas such as the yard or work area of the suspect(s).
  • Submit a map identifying soil-sample locations.
  • Do not remove soil adhering to shoes, clothing, and tools. Do not process tools for latent prints. Air-dry the soil and the clothing, and package separately in paper bags.
  • Carefully remove soil adhering to vehicles. Air-dry the soil, and package separately in paper bags.
  • Ship known and questioned debris separately to avoid contamination. Submit known and questioned soil in leakproof containers such as film canisters or plastic pill bottles. Do not use paper envelopes or glass containers. Pack to keep lumps intact.
Special-Event and Situational Awareness Support

Visual information specialists travel to the field and conduct digital site/venue surveys. These operations include three-dimensional laser scanning and documentation of physical structures and objects, 360-degree spherical video capture, and geographic information system (GIS) mapping.

Questions concerning special-event and situational awareness support should be directed to 703-632-8194.

Tape Examinations

Tape composition, construction, and color can be compared with known sources. Comparisons can be made with the torn end of tape and a suspect roll of tape.

The Laboratory will examine duct, vinyl electrical, packaging, masking, and cellulose acetate (e.g., Scotch) tapes.

Questions concerning tape evidence should be directed to 703-632-8441
. Follow the evidence submission directions, including
Requesting Evidence Examinations
and
Packaging and Shipping Evidence
.

  • Whenever possible, submit tape still adhered to the substrate. This minimizes the loss of trace evidence, latent fingerprints, or contact impressions. If it is not possible to submit the substrate, the tape may be manually removed and placed adhesive side down on a clean, colorless piece of plastic sheeting (e.g., transparency film or Kapak tubular rollstock), not on cardboard, paper, or vinyl document protectors. Do not distort or tear the tape during removal.
  • If the tape is cut during removal, document and initial each cut. Use a method that produces a unique cutting pattern (e.g., pinking shears).
Toolmark Examinations
Toolmarks

Tools can bear unique microscopic characteristics because of manufacturing processes and use. These characteristics can be transferred to surfaces that had contact with the tools. Evidence toolmarks can be compared with recovered tools. In the absence of a questioned tool, toolmark examinations can determine the type of tool(s) that produced the toolmark and whether the toolmark is of value for comparison. Toolmark examinations also include lock-and-key examinations.

Fractures

Fracture examinations sometimes can be used to determine whether evidence was joined together and subsequently broken apart.

Questions concerning toolmark evidence should be directed to 703-632-8442.
Follow the evidence submission directions, including
Requesting Evidence Examinations
and
Packaging and Shipping Evidence
.

  • If possible, submit the tool-marked evidence.
  • If it is not possible to submit the tool-marked evidence, make a cast to submit to the Laboratory.
    1. Use an acrylic-surface replica cast kit. Call the Laboratory at
      703-632-8442
      regarding the appropriate cast kit.
    2. Different formulas are used in different temperatures. If possible, move the evidence to a warm area.
    3. Casts will duplicate foreign material in the stamped characters. Clean the area before proceeding. Remove paint and dirt with a solvent such as acetone, gasoline, or paint remover. Use Naval Jelly to remove rust. Use a soft brush. Do not use a wire brush.
    4. Build a dam around the stamped characters to retain the acrylic liquid while it hardens. Use a soft and pliable dam material such as modeling clay. Ensure there are no voids in the dam.
    5. Following the instructions in the kit, mix the liquid and powder for one minute and pour the mixture into the dam.
    6. The acrylic liquid will take 30 minutes to harden. Remove the cast when it is hard. If paint and rust are on the cast, make additional casts and submit the cleanest one to the Laboratory.
    7. Indicate where on the object (often a vehicle) the cast was taken.
    8. Pack the cast to prevent breakage.
  • Photographs locate toolmarks but are of no value for identification purposes.
  • Obtain samples of any material deposited on the tools. Submit samples in leakproof containers such as film canisters or plastic pill bottles.
  • To avoid contamination, do not place the tool against the tool-marked evidence.
  • Submit the tool rather than making test cuts or impressions.
  • Mark the ends of the evidence and specify which end was cut during evidence collection.
Toxicology Examinations

The Toxicology discipline of the FBI Laboratory is accredited by the American Board of Forensic Toxicologists. Toxicology examinations can disclose the presence of drugs and poisons in biological specimens and food products. The examinations can determine the circumstances surrounding drug- or poison-related homicides, suicides, and accidents.

Because of the large number of potentially toxic substances, it may be necessary to screen for classes of poisons. Examples include:

  • Volatile compounds (ethanol, methanol, isopropanol).
  • Heavy metals (arsenic).
  • Nonvolatile organic compounds (drugs of abuse, pharmaceuticals).
  • Miscellaneous (strychnine, cyanide).

Questions concerning toxicology evidence should be directed to 703-632-8441.
Follow the evidence submission directions, including
Requesting Evidence Examinations
and
Packaging and Shipping Evidence
.

  • Accepting evidence in alleged poison investigations will be based on whether the victim(s) sought medical attention or a suspicious death occurred. A doctor’s medical evaluation and report must be included with the evidence.
  • Biological evidence in drug-facilitated assaults must include a urine sample. The urine must be collected as soon as possible after the assault but must not have been collected more than 96 hours after the alleged drugging.
  • Toxicological analysis of hair specimens will be performed only for specific drugs or poisons.
    Call the Laboratory at 703-632-8441 prior to submitting hair to ensure that the evidence will be accepted for examination.
    The communication accompanying the evidence must reference the telephone conversation accepting the evidence.
  • The quantity of biological specimens submitted depends on whether the identity of a toxic substance is known, the route of administration, the time after exposure that biological specimens are collected, and whether subjects(s) or victim(s) are living or deceased.
    Call the Laboratory at 703-632-8441 prior to submitting the specimens to ensure that the correct quantity is submitted.
    The communication accompanying the evidence must reference the telephone conversation accepting the evidence.
  • Each biological specimen must be placed in separate, labeled, sealed glass tubes, plastic cups, or heat-sealed or resealable plastic bags. Affix BIOHAZARD labels to the inside and outside containers.
  • Refrigerate or freeze biological specimens during storage and shipping to prevent deterioration. Pack so that no breakage, leakage, or contamination occurs.
  • Submit a copy of the autopsy or incident report.
  • Describe the symptoms of the suspect(s) or victim(s) at the time of the crime or prior to the death.
  • List any known or questioned drugs consumed by or prescribed for the suspect(s) or victim(s).
  • Describe any known or questioned environmental exposure to toxic substances by the suspect(s) or victim(s).
Video Examinations

Video examinations are conducted by the FBI’s Operational Technology Division (OTD), Digital Evidence Laboratory (DEL), Forensic Audio, Video, and Image Analysis Unit (FAVIAU). The OTD DEL has different acceptance criteria and a different physical address than the FBI Laboratory, as described below.

Authenticity

Authenticity examinations are conducted to determine whether video recordings are original, continuous, unaltered, and consistent with the operation of the recording device used to make the recording.

Enhancement

Enhancement examinations are conducted to maximize the clarity of the video signal.

Video Image Processing

Enhanced still images can be produced from images on video and made as prints or digital files.

Standards Conversion

Video can be converted from one standard to another (e.g., PAL to NTSC or SECAM).

Format Conversion

Video can be converted from one format to another (e.g., Beta to VHS).

Synchronization

Audio and video signals can be combined to produce one composite recording.

Special Effects

Special effects, such as a mosaic or blur spot, can be added to video recordings to protect a person’s identity.

Damaged Media Repair

Video recordings can be repaired, restored, or retrieved for playback and examination, if damage is not too extensive.

Questions concerning video examinations should be directed to 703-985-1393. Questions concerning video evidence should be directed to 703-985-1388
.

Video examinations may not be submitted directly from entities outside the FBI. State, local, or international agency cases must be submitted by the FBI field office servicing the area and must meet one of the following two criteria: 1) the state, local, or international case has a nexus to an ongoing FBI investigation or 2) the FBI division head deems that the case is of enough regional importance to merit the dedication of federal resources to the state, local, or international case. These criteria shall be met with a written statement from the division head (Special Agent in Charge). FBI entities may submit cases directly.

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

  • Write-protect the original media. Never use the Pause operation when viewing original video recordings.
  • Submit original video recordings. If originals cannot be obtained, call for further instructions.
  • Queue the original videotape to the approximate time of the pertinent area. State in a communication the date and time of the pertinent area, and use the date-time stamp on the video or the counter indicator (set from the beginning of the tape at 000).
  • Label the outer container “FRAGILE, SENSITIVE ELECTRONIC EQUIPMENT” or “FRAGILE, SENSITIVE AUDIO/VIDEO MEDIA” 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

Weapons of Mass Destruction Examinations

A weapon of mass destruction (WMD) is typically associated with nuclear and/or radiological, biological, or chemical agents; however, it also may be an explosive. WMDs are designed to cause a large amount of destruction or disruption to people and infrastructures.

The FBI Laboratory has formalized partnerships with a variety of government, academic, and private laboratories to conduct forensic examinations of evidence that either contains or is contaminated with hazardous chemical, biological, and/or radiological material.

Depending on the nature of the threat—i.e., chemical, biological, or radiological—evidence examinations will be conducted by the Laboratory or at a designated FBI partner laboratory specially equipped to handle hazardous materials.

The Laboratory can direct or apply the use of specialized analytical techniques to identify and characterize a wide range of biological pathogens, toxins, chemical agents, toxic chemicals, and trace radioactive compounds that constitute a suspected or potential WMD.

The FBI’s Hazardous Evidence Analysis Team (HEAT), composed of forensic examiners and technicians from the various FBI Laboratory disciplines, is trained to safely conduct traditional examinations of hazardous evidence. These examinations are conducted at FBI partner laboratories.

Suspected or onfirme rme ene should be handled only by qualified personnel.

Upon notification or suspicion of a possible WMD incident, contact the FBI’s Strategic Information and Operations Center at 202-323-3300 and ask for the Weapons of Mass Destruction Operations Unit Duty Officer.

Before it can be analyzed by the Laboratory or partner laboratories, suspected or confirmed WMD evidence must be properly field-screened by qualified personnel to determine the absence or presence of hazardous materials.
Questions concerning WMD evidence examinations should be directed to 703-632-7766.

BOOK: FBI Handbook of Crime Scene Forensics
5.51Mb size Format: txt, pdf, ePub
ads

Other books

The Warrior Sheep Go West by Christopher Russell
Descendant by Lesley Livingston
Swept Away by Candace Camp
The Viceroy of Ouidah by Bruce Chatwin
A Big Year for Lily by Mary Ann Kinsinger, Suzanne Woods Fisher
Chanda's Wars by Allan Stratton
When I'm Gone by Katilyn S
Dinner for One by Meg Harding