FBI Handbook of Crime Scene Forensics (8 page)

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.
  

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 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).
  

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 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.

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.