Crime Scene & Death Investigation; how death c/b ______ is shown

Chain of custody

 the documented and unbroken transfer of evidence.

Circumstantial evidence

Indirect evidence that can be used to imply a fact but does NOT directly prove it, only the suspect and victim see the evidence left at the crime scene (understanding how it was used, but examiners can only IMPLY bc. they weren’t there)

Class evidence

material that connects an individual or thing to a certain group (see individual evidence).

Crime-scene investigation

 a multidisciplinary approach in which scientific and legal professionals work together to solve a crime

Crime-scene reconstruction

a hypothesis of the sequence of events from before the crime was committed through its commissions

Direct evidence

evidence that (if true) proves an alleged fact, such as an eyewitness account of a crime;Firsthand observations such as eyewitness accounts or police dashboard video cameras

Individual evidence

 a kind of evidence that identifies a particular person or thing

Paper bindle

a folded paper used to hold trace evidence

Primary crime scene

- the location where the crime took place.

Secondary crime scene

a location other than the primary crime scene, but that is in some way related to the crime, where evidence is found.

Trace evidence

 small but measurable amounts of physical or biological material found at a crime scene

Goal of Crime-scene investigation

recognize, document and collect evidence at the scene of a crime

Who documented the crime scene and collects physical evidence?

crime-scene investigators

Typically first to arrive on scene:

police officers; district attorney may be present if search warrant is necessary

Circumstantial Evidence can be either__________

Biological (ex: body fluids, hair, etc.) or physical (ex: fingerprints, footprints, tire impressions, etc.), or TRACE EVIDENCE

What determine the extent of trace evidence?

intensity, duration, and nature of materials in contact

Example of trace evidence:

Located used evidence from under a female victim’s fingernails to help identify her attacker

Trace evidence bears a ___________ to a crime

silent witness

Who can trace evidence be found on (remember physical transfer=trace evidence)

both persons

Dr. Edmond Locard’s Principle of Exchange

When a person comes into contact with an object or another person, a cross-transfer of physical evidence can occur

Physical transfer of evidence

two people come into contact with eachother

Medical examiners role in crime-scene investigation:

determine probable cause of death

Detectives role in crime-scene investigation

look for leads by interviewing witnesses and talk to the crime-scene investigators about the evidence

Forensic Specialist such as ____________ may be consulted if evidence requires their expertise

entomologist, forensic psychologists

The Seven “S’s” of Crime-Scene Investigation

Securing the scene, Separating the witness, Scanning the scene, Sketching the scene, Searching for evidence, Securing and Collecting evidence

Securing the scene is the responsibility of whom?

police officer (first responder)

What is first priority for securing the scene? what’s second?

safety of all individuals, preservation of evidence

Separating the witnesses prevents…

witnesses working together to create a story (collusion)

Example of primary crime scene and secondary crime scene

robbery in front of a store- primary, and the home of a suspect-secondary

place of murder-primary, where course is found- secondary

Seeing the scene means_______needs to see the scene and photos of overall area and close-up photos with an without a __________ should be taken and taken at different_________.

crime scene examiner, measuring ruler, angles

In sketching the scene…

accurate rough sketch, all objects should be measured from two immovable landmarks, north should be labeled, scale of distance provided, everything included even if outside, final copy of crime scene should be made for court

Searching for evidence can depend on the number of what?

investigators

In searching for evidence what patterns should be walked?

spiral, grid, linear

In searching for evidence the locations of evidence is:

marked, photographed, and sketched

Single investigators use what pattern

grid, linear, or spiral

A group of investigators uses what pattern

linear, zone, or quadrant

What tools avoid picking extraneous (not important) material?

flashlight and forceps

In searching for evidence patterns are_____and ensure______?

systematic, that no area is left unsearched

In securing and collecting evidence, evidence needs to be_______

properly packaged, sealed, and labeled

In securing and collecting evidence liquids and arson are_____

stored in airtight, unbreakable containers

In securing and collecting evidence, biological or wet evidence is____

stored in breathable containers so the evidence can dry out and mold contamination is reduced

Biological evidence, once dried and after being stored in breathable containers, is____

packaged in a paper bindle and placed into a plastic or paper container; the outer containers is sealed with tape and labeled with the signature of the collector

Evidence is ______ by the collector

signed with his/her name

One of the largest forensic crime labs in the world

FBI crime lab

What lab processes all evidence collected

forensic lab

Who are and what do forensic lab techs do

specialized in one particular forensic field (ex:entomology) and process one type of evidence

Who are lab RESULTS sent to

the lead detective

What do test results lead to

crime-scene reconstruction

Crime Scene Reconstruction

Forming a hypothesis of the sequence of events from before the crime was committed through its commission.

Who determines how evidences fits into the overall crime scenario

detectives

Evidence is explained and compared to what to determine the reliability of what?

witnesses’ statements to determine the reliability of their accounts

Acquit

free someone from a criminal charge by a verdict of not guilty

Evidence doesn't lie but can be_____

staged

Common situations in which a crime scene is staged

arson (often used to cover up other crimes like murder), suicide/murder (can be staged to look like a suicide), burglary (staged to collect insurance money)