Observations
How does a trained forensic investigator collect evidence?
Collects all available evidence without judgment of its potential importance
The goals of crime scene investigation
Piecing together the evidence
- Fact-based evidence.
- Includes firsthand observations.
Direct evidence
a permanent fixed point of reference used in mapping a crime scene
datum point
how do you store blood evidence
paper envelope or bag, must be breathable
What affects ones ability to observe?
level of interest, Stress, Concentration, amount and kind of distractions present, prejudices , personal belief, Motives, lapse in time since the event
Who can be part of the crime scene investigation team?
Police officers, District attorneys, Crime scene investigators, Medical examiners, Detectives, Specialists
Consists of bodily fluids and tissues.
Biological evidence
the ability to identify a concept or problem, isolate its component parts, organize information for decision making, establish criteria for evaluation, and draw appropriate conclusions
analytical skill
Evidence that is consistent when it is retested and was properly collected and analyzed using accepted protocols is considered _____
reliable and valid
What three things must a forensic investigator be able to do?
Find, record, interperet
When two entities come into contact and physical transfer occurs. The intensity, duration, and nature of the contact determines the extent of the transfer.
Locard's Principle of Exchange
Narrows the identity of a suspect or item to a specific
person or object.
Individual Evidence
information received from the senses
perception
A suspect confessed during interrogation but was never read their Miranda rights. Can this be used in court
No
Deriving conclusions from facts using a series of logical steps
Deductive Reasoning
The seven S's of Crime scene investigation
1. Secure the scene (first responders)
2. Separate Witnesses
3. Scan the scene, decide where to take photos
4. See the scene, take photos
5. Sketch the scene
6. Search for evidence, find patterns
7. Secure and collect evidence
Type of physical evidence found in small quantities
(often in microscopic amounts).
Trace Evidence
a person who saw someone or something related to a crime and can communicate their observation
eyewitness
saliva found at a crime scene would be _____ evidence
biological
Research that found that 75% of wrongful convictions were due to faulty eyewitness statements
The Innocence Project
What should be included in a crime scene sketch?
- Case number, Date and time, Location, Arrow to indicate north, Sketch Artist, Evidence numbers, Key that correlates to evidence numbers
- locations of door and window, furniture, but measurement not necessary, Measure to center of every piece of evidence at right angles to two nearest walls: write measurements on the sketch, Measure from the center of the victim’s head
Evidence used to imply a fact, but not directly prove a fact (indirect).
Circumstantial Evidence
the documented and unbroken transfer of evidence
chain of custody
marriage and divorce are examples of _________
civil law
What are the steps to the Scientific Method?
1. Make and observation
2. Propose a hypothesis
3. Design experiment
4. Collect data
5. Analyze data
6. Draw conclusions based on data
Give 3 examples of commonly faked crimes scenes
1. Arson to cover other crimes
2. Murder staged to look like suicide
3. Burglary to collect insurance money
Any object that can connect a victim or suspect to a crime scene.
Is objective and, when documented, collected and preserved properly, may be the only way to reliably place or link someone to a crime scene.
Physical Evidence
a possible explanation of a question or problem based on prior knowledge or observation (educated guess)
hypothesis
what does ATF stand for?
Alcohol, Tobacco, and Firearms