CS Chapter 1

CS processng consists of

examination and evaluation of the scene to recover physical evidence and document the conditions in situ

CS six basic steps

assessing, observing, documenting, searching, collecting, and analyzing

Two basic goals of police

prevention of crime and disorder, and the preservation of peace; protection of life, property and personal liberty

Police’s five basic objectives

Crime prevention, crime repression, regulatin noncriminal conduct, provision of services and protection of personal liberty

Which police objectives are related to crime scene

crime repression by conducting objective investigations and protection of personal property

Ethics: true duty of CS investigator

remain professional and objective, search for the truth

crime prevention

actions and efforts designed to keep crime from occuring; community and youth programs, proactive patrol,

crime repression

When prevention fails, repress the criminal by actively investigating crimes adn identify those responsible

regulating non-criminal conduct

control general behaviors; compliance with city ordinances and traffic regulations

provision of services

The scope and breadth of police work is very broad

protection of personal liberty

mandate to protect citizens from unwarranted police interference with their personal liberties. Police must actively control their own behavior to ensure their practices abide by constitutional law

Evidence

anything that tends to prove or disprove a fact in contention. Function of time and the item’s surroundings: evidence issue is of context more so than of content

testimonial evidence

interviews, interrogations of witnesses, victims, and suspects or subjects. A flaw is human subjectivity and our ability to perceive and remember events

physical evidence

Specific items found at the scene that are often collected for subsequent analysis. Can also be context though photogrpahs or sketching. Physical evidence is real, tangible, and cannot be denied; it never lies. Establishes facts and provides objective knowledge. Failure is human misinterpretation.

Value of evidence/context: predictable effects (Chisum & Rynearsons effects)

changes to the scene or evidence that occur with rhythm or regularity. Ex. entomology and the stage of insect activity to establish time of death, rigor, and livor mortis

Value of evidence/context: unpredictable effects (Chisum & Rynearsons effects)

changes that occur unexpectedly or randomly, altering the original scene and evidence. Ex. entry of police/EMS, disturbance of an item of evidence. order in which we process the CS is to prevent unpredictable effects

Value of evidence/context: relational details (Chisum & Rynearsons effects)

CSI ability to physically place items on the scene and correlate different objects. Ex. presence of a void pattern, cluster of cartridge cases on grass, weapon in close proximity to victim. Crime scene sketches are important for this reason.

Value of evidence/context: transitory effects (Chisum & Rynearsons effects)

Fleeting, fails to stand out to CSI. Time and environment can destroy transitory effects. First responders are often expected to make note of this. Ex. heat of burning cigar, presence of ice in a glass, odors.

Value of evidence/context: functional details (Chisum & Rynearsons effects)

operating conditions of items on the scene. Help disprove allegations or help define when crime scene occurred. Ex. is a weapon capable of operating in normal fashion, was clock alarm set to a specific time, deadbolt operates normally.

Questions to consider when considering each item observed in the scene

What is it, what function did it serve, what relationship does it have to any other items of evidence or the scene itself, and what does it tell us about timing and sequencing aspects

Forensic linkage triangle

each item discovered must be considered as a mechanism for linking the scene, the victim, or suspect

Timing aspect of evidence at crime scene

place the time of the crime in some form. Ex. meals that are in preparation or completed, stomach contents at autopsy, alarms, clocks or timers that are set but have yet to go off

Sequencing aspect of evidence at a crime scene

What order the crime occured. Ex. disturbance of bloodstain by shoe mark, order in which items are layered on the floor, radial cracks from bullet holes in pane glasss

five key ingredients to consider for good processing methodology

knowledge, skills and tools, flexibility, methodical approach, and coordinated effort

Three scene integrity issues

addition, destruction, and movement of material

Addition of material

referred to as post incident artifacts, evidence that was not there to begin with. Every contact leaves a trace.

destruction of material

loss of an item’s evidentiary value

movement of material

often the result of investigative processing techniques, and affects the relational aspects observed

investigators standard when pursuing a solution to a crime

investigate to the point of beyond a reasonable doubt

What is part of good investigative ethics

must collect and document the evidence as they find it, cannot pick and choose what to report,