Crime Scene Investigation

Circumstantial Evidence

Evidence that can imply facts but not directly prove it may link suspects and crime scenes ex: weapon used

Direct Evidence

evidence that directly proves a fact with nothing more needed, ex:surveillance videos, confessions

Chain of Custody

Record of who has handled/collected/stored evidence to see of anyone has tampered with it

Locards principle of exchange

When a person comes into contact with an object or another person a cross-transfer of physical evidence can occur."everything leaves a trace”

class evidence

Narrows an identity of a group of people of things ex:blood type, clothing fiber, hair sample

individual evidence

evidence that can be linked to a single person ex: fingerprints, DNA

physical evidence

object that can u used to prove something in a crime, fingerprints, DNA, weapon, clothing piece, footprints, tire marks

biological evidence

physical evidence from an orgaism ex:blood, hair, saliva

eyewitness testimony

when someone tells what they saw happen at a crime scene, usually used in court to establish facts

paper bindle

folded pice of paper to store small things like fingernails or hair to transfer it later placed in bag to prevent contamination

primary crime scene

the location where the actual crime happened

secondary crime scene

evidence related to the crime is found, but not directly where the crime occurred ex:moved dead body, car, hospital

trace evidence

small/microscopic evidenceleft behind that can be used to link a suspect or location, ex:clothing fiber broken glass

crime scene investigator

responsible for identifying/collecting evidence in a crime scene to solve a case

Securing the Scene

Making sure everyone in the area is safe and isolating the area to preserve evidence and prevent tampering

Seperating the witnesses

Seperate witnesses to get different stories and ask what they saw happen, detectives do not want witnesses to work together to create a story that isnt authentic

STEP 2

scanning the scene

before taking photos to determine where they should be taken and where potential evidence is to establish a detailed investigation

STEP 3

Seeing the scene

photographs of all angles and perspectives are taken after scene is secured

STEP 4

Sketching the scene

Sketching a detailed drawing either professionally or at the scene with measurements/scale to document what can’t be seen in photos

STEP 5

Searching the scene

Examaning the crime scene using area patterns to identify potential evidence

STEP 6

Securing and collecting evidence

packaging, securing, labeling, collecting evidence to maintain chain of custody and prevent contamination or loss

STEP 7

Who are the poeple part of the crime scene investigation team?

CSI, forensic photographers, police, detectives, forensic artists, forensic examiners

Mistakes made with the chain of custody

Mishandling- cross contamination, unsecures

Mislabeling or loss of evidence- incorrect tags

Improper documentation- missing logs, incomplete paperwork failure to record transfers

why is the chain of custody important?

To know who has the evidencewhen and see if anyone had tampered with it