Ch 3 Flashcards
The successful management of a crime scene involves three major functions.
- the responding officers whose responsibility is to render the crime scene safe and to control movement of persons and officers into and out of the area.
- crime scene investigators who conduct the search for evidence and also prepare the proper documentation of the crime scene.
- search for witnesses.
Approach
responding officers should be alert to any suspects or witnesses who are leaving the scene.
Safety
Neutralization of the crime scene includes the arrest of any suspects and the elimination of any hazards that might present a threat, such as a clandestine drug laboratory.
Medical attention
ensure that medical attention is provided if required with as little impact on the crime scene as possible. limiting the number of persons who enter the area and respect the need to minimize the possible destruction of evidence.
Search for Witnesses
separate them as soon as possible.
When witnesses discuss the crime or overhear others talking about the crime, they tend to adopt some of this information as their own or alter their recollections to fit with those of other witnesses. This process is normal and is known as retroactive interference.
refusal to give information or their statement of ignorance should be properly recorded in the police report.
Broadcast Alarm
obtain a suspect and vehicle description. Once this information is obtained, the investigator should broadcast this information
Scene Boundaries
“Crime Scene” barrier tape aids in delineating the crime scene area. Officers posted at the perimeter will also prevent the entry of unauthorized persons. Crime scene boundaries should be established beyond the initial scope of the crime scene with the understanding that the boundaries can be reduced in size if necessary but cannot be easily expanded.
chronological log of events as they occur at the scene. This is typically a time-based log that documents when an officer enters and leaves the scene. Scribe
Search Procedures
investigator surveys the scene, noting its dimensions and the presence or absence of an adjoining entry (approach) and exit (flight) area.
- A point-to-point movement, following a chain of objects that are obviously evidence
- An ever-widening circle technique, in which the searching officer starts at the focal point of the scene or the center of the security area and works outward by circling in a clockwise or counterclockwise direction until the fringes of the protected area are reached
- An ever-narrowing circle, the reverse of an ever-widening circle, in which the searching officer starts at the outskirts of the crime scene and works toward its focal point
- A zone or sector search in which the scene is subdivided into segments and each sector is searched as an individual unit
grid search begins after the strip search is completed. It covers the same area in a similar manner but at right angles to the previous search pattern. Metal or wood stakes and heavy cord are used to direct and control outdoor searches.
Disinterested witness
delay such a search until it can be made in the presence of a disinterested witness and also require the investigator to record the name of such a witness in his or her field notes. A complete list of all property found on the deceased victim, as well as where it was found (e.g., right-side pocket of trousers, hidden in bra), are made part of the officer’s notes.
modus operandi
method of operation of the offender.
In assaults and homicides, the injuries sustained by the victim suggest a weapon and orient the search toward it.
In burglaries, the means used to gain access to the premises and the place of entrance indicates the possible location of tool marks. Tabletops, glassware, and other smooth surfaces guide the search for imprints.
Soft earth, mud, and dust are known sites for foot and tire impressions.
Locard’s exchange principle
suspects will bring items of evidence into the crime scene and will take items with them when they leave. This exchange of trace evidence involves such items of evidence as hairs, fibers, dirt, dust, blood, body fluids, skin cells, and other microscopic materials.
Collecting evidence
Investigators should not rush to pick up evidence since its significance may be destroyed in doing so. The investigator’s field notes should record the discovery. In addition, photographs and accurate measurements are necessary to show the original position and nature of all evidence. In searching for evidence at crime scenes, never alter the position of, pick up, or touch any object before it has been described in minute detail in an official note and photographed.
Evidence groups
(1) weapons,
(2) blood and body fluids,
(3) imprints or impressions (traces of a person or a vehicle),
(4) marks of tools used to gain access to locked premises or containers,
(5) dust and dirt traces,
(6) questioned documents, and
(7) miscellaneous trace or transfer evidence, including such items as hairs, fibers, and skin cells.
Counterfeit money evidence
should have a dual marking. The name of the person last in possession should be signed across a corner of the bill, or such person should be asked to scratch his or her initials on a coin. In addition, the investigator should place his or her own mark of identification on the money.
Chain of Custody
evidence should not be disturbed until its location and nature can be brought to the attention of the responsible investigator, nor should it be moved until its location and description have been noted, photographs have been taken at the scene, and measurements have been made to place it.