chapter 2 Flashcards
Physical evidence
Any object that can establish that a crime has or has not been committed or can link a crime and its victim or its perpetrator
First Responder
Responsible for preserving and protecting the area as much as possible. Special notes of vehicles or people leaving the scene. Frist priority should be obtaining medical assistance for ppl in need of it and to arresting the perp. extensive efforts must be made to exclude all unauthorized personel from the scene… must evaluate victims condition and record any statements made by victim, must keep an accurate log of all in the area boundaries should encompass entree and exits, once scene is secure, investigator can proceed with an initial walk through of the scene to gain an overview of the situation and develop a strategy for systematically examining and documenting the crime scene.
Miranada Warning
You have the right to remain silent. Anything you say can and will be used against you in a court of law. You have the right to speak to an attorney, and to have an attorney present during any questioning. If you cannot afford a lawyer, one will be provided for you at government expense.
Crime scene secured
boundaries should encompass the center of the scene where the crime occured any paths of entry/exit and any areas where evidence may have been discarded or moved. Ropes/barricades along with strategic positioning of guards… efforts must be taken to identify all individuals at the scene and detain all potential suspects or witnesses.
Recording the crime scene
Notes, photography, sketches - 3 methods used. Notes should include, indenifying the person who contacted the investigator, the time of the contact & any preliminary information disclosed, case # should be recored who is present, identities of any personnel who are being contacted, names titles time of arrival. A precise record of personnel movements in and out of the scene. tasks assigned to different members noted,if a victim is found the officer must evaluate the body and make notes, tape recorder could be faster, photography- good for showing the layout of the scee, the position of evidence to be collected and the relation of objects at the scene to one another. Also important for documenting biological evidence in its original condition, as this evidence gets altered during testing. photos of entry, exits, positions of evidence,
Strip or Line search
One or two investigators start at the boundary at one end and walk straight across to the other side,
Grid Search Pattern
Two ppl, performing line searches that originate for adjacent corners and form perpendicular lines. very thorough, but boundaries must be well established.
Spiral search Pattern
One person, investigator can move inward spiral from the boundary to the center or an outward spiral from the center to the boundary.
Wheel or Ray search pattern
Employs several ppl moving from the boundary straight toward the center of the scene inward, or from the center outwards (rays) this is not preferred because space between the rays can be missed.
Quadrant or one search pattern
Divides the scene into zones or quadrants, tam members are assigned to earch each section. sections can be subdivided. this method is best suited for scenes that cover a lare area. the areas searched must include all probable points of entry and exit used by the criminals.
Collecting and packaging physical evidence
- Victims clothing
- Fingernail scrapings.
- head & pubic hairs
- Blood for DNA purposes
- Vaginal, anal, and oral swabs (Sex related crimes)
- Recovered bullets from the body
- Hand swabs from shooting victims (gunshot residue)
Biological materials
only use disposable tools to collect biological materials. Use paper bags/ envelopes, pill bottles, air dry all items possibly containing biological fluid evidence place them individually in separate paper bags to ensure a constant circulation of air through them..
DNA evidence
saliva, dead skin cells, sweat… cups/cans/ gum/ sweatband/ bed sheet..
Prevent contamination
no eating, no using the toilets, frequent changing of latex gloves, disposable forceps, face mask so no sneezing into evidence…..
Maintaing Chain of Custody
Continuity of possession, or the chain of custody, must be established whenever evidence is presented in court as an exhibit. (A list of all ppl who came into possession of an item of evidence) Failure to substantiate the evidences chain of custody may lead to serious quesitons regarding the authenticity and integrity of the evidence and examinations of it.
