Criminal Investigations Exam I

Criminal Investigation

process of collecting crime related info to reach certain goals

Reactive criminal investigation

4 stages, a crime happens, police react to it, investigation might occur

Proactive criminal investigation

undercover operations, LEO initiated surveillance

Probability error

probability that coincidences are considered to be actual evidence

Tunnel vision

when an investigator only focuses on a particular person or range of alternatives and excludes other possibilities

Confirmation bias

investigator only follows one part of the evidence even there is contrary evidence

Judicial evidence

evidence that meets the judiacila standard and can be used in court

extrajudicial evidence

any info on which an investigative decision can be based on but not allowed in court

Exculpatory evidence

evidence that excludes a suspect

Inculpatory evidence

evidence that includes a person as a suspect

proof

certainty that a fact/conclusion are true

standards of proof

different levels by which uncertainty about a fact can be eliminated

Probable cause

standard needed to justify a search/arrest

reasonable suspicion

standard for police to stop and search a person

Beyond a reasonable doubt

standard to convict someone

Preponderance of evidence

standard relevant in civil law and trials

Direct evidence

evidence that directly demonstrates a fact

Indirect evidence

evidence that requires inferences in order to draw a conclusion

testimonial evidence

evidence from person under oath in court

lay witness

someone who testifies to what they saw

Expert witness

provides testimonial evidence based on expert knowledge on an issue

Hearsay

secondhand info

real evidence

evidence produced as a direct result of a crime occurring

Demonstrative evidence

objects produced indirectly from a crime that relate to the crime

Documentary evidence

evidence that is a document

corpus delicti

helps establish that a crime occurred

corroborative evidence

supplements and strengthens already existing evidence

cumulative

duplicates but does not necessarily strengthen existing evidence

Associative

links people,places, and things to each other

Indentificative

evidence that ID’s a person

Behavioral

provides a basis on which to identify the characteristics of the person who committed the crime

Arrest

occurs when the police take a person into custody for criminal prosecution and interrogation

Custody

not free to leave

Arrest warrant

document issued by a judge so the police can arrest someone

search

gov’t infringement into a person’s reasonable privacy for the purposes of discovering evidence

search warrant

document issued by a judge that authorizes a search of a person for evidence

relevant evidence

evidence that relates to the case at hand

material evidence

significant and proves a fact

compotent

evidence that is valid and quality

Frye Test

legal test for scientific evidence that must be generally accepted by the scientific community

Daubert Standard

legal test for scientific evidence; must be based on scientific knowledge

Necessary evidence

evidence used to establish a legit point

chain of custody

record of individuals who maintained control over physical evidence

Exigent circumstances

emergency situations where searches can happen without a warrant

Vehicle exception

exception to SW requiremnt that allows police to search a vehicle

Pretext traffic stop

a traffic stop made for any traffic offense that allows for other LEO action

other places exception

exception to search places without a SW where there is no expectation of privacy

hot pursuit exception

exception to SW if police are in pursuit of a suspect

search incident to arrest exception

exception to SW where police can search a person and things when that person is arrested.

search and frisk exception

exception to SW so police can search outer clothing based on reasonable suspicion of criminal activity

plain view exception

exception when evidence is in plain site

consent exception exception

exception when police receive consent to search

knock and talk search

search where police talk in an attempt to obtain consent to search the home

Exclusionary rule

if search is unreasonable, evidence is not allowed in court

good faith exception

when police make a mistake in conducting search, evidence can be used in court

inevitable discovery exception

when the police reasonably expect to discover evidence through legal means

purged taint/passage of time

illegal actions of the police can be overcome by voluntary actions of the suspect

evidence from independent sources

evidence from independent source not related to illegal search can be used in court

Miranda warnings

a list of rights that must be provided to a suspect in custody and prior to interrogation

physical evidence

forensic evidence, evidence that can be seen/held that is created as a direct result of a crime

class characteristics

features of forensic evidence that allow it be associated with a group

Individual characteristics

forensic evidence that allow it to be associated with a particular source

crime scene

place where crime occurred or where evidence is located

cross contamination

investigators inadvertently transfer evidence from one scene to another

neighborhood canvass

door-to-door questioning of residents near crime scene

CODIS

combined DNA Indexing system, database from FBI with DNA profiles of various sources

FDS

familial DNA searching, genetic genealogy searching for similar but not exact DNA matches