forensics chapter 1 & 2

analytical skills

ability to identify a concept or problem, to isolate its component parts, to organize information for decision making, to establish criteria for evaluation, and to draw appropriate conclusions

deductive reasoning

deriving the consequences from the facts using a series of logical steps

eyewitness

a person who has seen someone or something and can communicate these facts

fact

a statement or assertion of information that can be verified

forensic

relating to the application of scientific knowledge of legal questions

logical

conclusions drawn from assumptions and known facts

observation

what a person perceives using his or her senses

opinion

personal belief founded on judgement rather than on direct experience or knowledge

perception

interpreting information received from the senses

chain of custody

documented and unbroken transfer of evidence

circumstantial evidence

material that connects an individual or thing to a certain group

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 commission

direct evidence

evidence that, if true, proves an alleged fact, such as an eyewitness account of a crime

first responder

the first police officer to arrive at a crime scene

individual evidence

a kind of evidence that identifies a particular person or thing

paper bindle

a folded paper used to hold its trace evidence

primary crime scene

the location where the crime took place

secondary crime scene

a location other than the primary 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

forensics

relating scientific knowledge to legal questions; what a person perceives using 5 senses sight, taste, hearing, smell, touch

how information is processed in our brain

information from our senses → what we pay attention to → perception → short-term memory → long-term memory

distinguish between observation, opinion, hypothesis, deductive reasoning, perception, fact

• observation: gathering data from five senses

• opinion: personal opinion, belief, value statement that cannot be proven true or false, reflect individual preferences

• hypothesis: testable explanation for an observation

• deductive reasoning: broad, general premise and narrows down to a conclusion

be familiar with innocence project and how it developed

found that 87% of their wrongful conviction cases resulted from flawed eyewitness testimony - they exonerate and free prisoners who they believe have been wrongly convicted

Locard’s Principle of Exchange

second part of Locard’s Principle states “the intensity, duration and materials determine the extent of transfer”

ex. investigators look for evidence like hair, fibers, skin cells, soil, and fingerprints to link suspects to victims

class evidence

narrows to a group of persons or things (physical or biological)

individual evidence

unique to one individual (DNA, fingerprints)

criminal trial

a trial where the state prosecutes an individual for a crime. the consequence can include jail time and fines

civil trial

a trial involving a legal dispute between two or more parties (individuals or businesses). outcome typically monetary damages or other specific relief, rather than jail time. medical and research trials

bench trials

trial where judge acts as the sole decision-maker, weighing the evidence and delivering the verdict. this happens when the defendant waives their right to a jury

jury trial

a trial where a group of citizens (the jury) listens to the evidence and is responsible for deciding the verdict

class evidence example

ABO blood type narrows field to anyone who is ABO but excludes anyone who is not ABO

individual evidence example

fingerprints, DNA

crime scene investigation team (1)

• police officers usually 1st to arrive

  • DA may also be present to determine if search warrant is necessary

crime scene investigation team (2)

• crime scene investigator

• documents and collects evidence

• photos, datas, collections

crime scene investigation team (3)

• medical examiner or coroner

• determines cause of death

crime-scene investigation team (4)

• detectives

• looks for leads

• talks to witnesses & CSI about evidence

crime-scene investigation team (5)

• specialists

• entomologists, archaeologist, serologist, toxicologist, odontologist, etc

• may or may not be needed

types of forensic serology evidence

1. dentine

2. soft tissue

3. blood and blood stains

4. keratinized tissue

5. saliva and saliva stains

6. calcified tissue

7. semen

7 S’s of crime scene investigation

1. secure scene

2. separate witnesses

3. scan the scene

4. “see” the scene

5. sketch the scene

6. search for evidence

7. secure and collect evidence

staged crime scenes

• arson (to cover another crime scene)

• suicide/murder (make scene look like suicide)

• burglary (staged to look)

paper bindle

paper bindle is where the trace evidence is allowed to air dry, and placed in evidence bag

for search of evidence,

spiral, grid, linear, or quadrant pattern should be walked & location of evidence marked

charges found along with coverups of crimes

prosecutors add obstruction and concealment charges, tampering with evidence, making false statements & perjury