[ Pobierz całość w formacie PDF ]
offender during the commission of the crime and taken away by him or her. Such questioned evidence can be compared with evidence of a known source and can thereby be associated/linked to a person/ vehicle/tool of a crime. 3. Evidence of an unknown/questioned source recovered from several crime scenes may also be used to associate multiple offenses that were committed by the same person and/or with the same tool or weapon. Samples whose source is known are of three basic types: 1. A standard/reference sample is material of a verifiable/docu- mented source which, when compared with evidence of an unknown source, shows an association or linkage between an offender, crime scene, and/or victim (e.g., a carpet cutting taken from a location suspected as the point of transfer for comparison with the fibers recovered from the suspect s shoes, a sample of paint removed from a suspect vehicle to be compared with paint found on a victim s vehicle following an accident, or a sample of the suspect s and/or victim s blood submitted for comparison with a bloodstained shirt recovered as evidence). 2. A control/blank sample is material of a known source that presumably was uncontaminated during the commission of the crime (e.g., a sample to be used in laboratory testing to ensure that the surface on which the sample is deposited does not interfere with testing. For example, when a bloodstain is collected from a carpet, a segment of unstained carpet must be collected for use as a blank or elimination sample). 41 3. An elimination sample is one of known source taken from a person who had lawful access to the scene (e.g., fingerprints from occupants, tire tread impressions from police vehicles, footwear impressions from emergency medical personnel) to be used for comparison with evidence of the same type. Contamination: The unwanted transfer of material from another source to a piece of physical evidence. Control/blank sample: See comparison samples. Cross-contamination: The unwanted transfer of material between two or more sources of physical evidence. Documentation: Written notes, audio/videotapes, printed forms, sketches and/or photographs that form a detailed record of the scene, evidence recovered, and actions taken during the search of the crime scene. Dying declaration: Statements made by a person who believes he or she is about to die, concerning the cause or circumstance surrounding his or her impending death. Elimination sample: See comparison samples. Evidence identifiers: Tape, labels, containers, and string tags used to identify the evidence, the person collecting the evidence, the date the evidence was gathered, basic criminal offense information, and a brief description of the pertinent evidence. First responder(s): The initial responding law enforcement officer(s) and/or other public safety official(s) or service provider(s) arriving at the scene prior to the arrival of the investigator(s) in charge. Impression evidence: Objects or materials that have retained the charac- teristics of other objects that have been physically pressed against them. Initial responding officer(s): The first law enforcement officer(s) to arrive at the scene. 42 Investigator(s) in charge: The official(s) responsible for the crime scene investigation. Known: See comparison samples. Latent print: A print impression not readily visible, made by contact of the hands or feet with a surface resulting in the transfer of materials from the skin to that surface. Measurement scale: An object showing standard units of length (e.g., ruler) used in photographic documentation of an item of evidence. Multiple scenes: Two or more physical locations of evidence associated with a crime (e.g., in a crime of personal violence, evidence may be found at the location of the assault and also on the person and clothing of the victim/assailant, the victim s/assailant s vehicle, and locations the victim/assailant frequents and resides). Nonporous container: Packaging through which liquids or vapors cannot pass (e.g., glass jars or metal cans). Other responders: Individuals who are involved in an aspect of the crime scene, such as perimeter security, traffic control, media manage- ment, scene processing, and technical support, as well as prosecutors, medical personnel, medical examiners, coroners, forensic examiners, evidence technicians, and fire and rescue officers. Personal protective equipment (PPE): Articles such as disposable gloves, masks, and eye protection that are utilized to provide a barrier to keep biological or chemical hazards from contacting the skin, eyes, and mucous membranes and to avoid contamination of the crime scene. Porous container: Packaging through which liquids or vapors may pass (e.g., paper bags, cloth bags). Presumptive test: A nonconfirmatory test used to screen for the pres- ence of a substance. 43 Projectile trajectory analysis: The method for determining the path of a high-speed object through space (e.g., a bullet emanating from a firearm). Radiological threat: The pending exposure to radiation energy. (This [ Pobierz całość w formacie PDF ] |