Crime and Science Investigation Midterm

Bow Street Runners

Founded by Henry Fielding; early police specialists.

London Metropolitan Police

Established by Sir Robert Peel in 1829; first full-time paid police force.

Scotland Yard

Created in 1839; detective bureau established in 1842.

Inductive reasoning

Uses specific examples to identify general patterns.

Deductive reasoning

Uses general principles to reach a specific conclusion.

CSI Effect

Jurors expect more forensic evidence because of crime TV shows.

Main objectives of criminal investigation

Detect crime, identify suspects, collect evidence, arrest suspects, recover property, and prepare prosecution.

Preliminary investigation

Initial investigation to determine what happened and preserve evidence.

Crime scene investigator (CSI)

Trained investigator who identifies, collects, and preserves crime scene evidence.

Five steps of report writing

Collect information, take notes, organize, write, and proofread.

Essential police report contents

People present, findings, actions taken, injuries, weapons, evidence, and statements.

Field notes

Chronological notes recording scene details, evidence, injuries, and observations.

Verified facts vs. opinions

Verified facts are supported; opinions are judgments or unsubstantiated claims.

General crime scene photographs

Show the overall scene and its surroundings.

Medium-range photographs

Show an evidence item's location within the scene.

Close-up photographs

Show small details of evidence, with and without a scale.

Crime scene sketch: coordinate method

Measures an item from two fixed reference points.

Crime scene sketch: cross-projection method

Shows an indoor room from above with walls folded down.

Crime scene sketch: triangulation method

Measures an item from two fixed objects in an outdoor scene.

Physical evidence

Material that can connect suspects to a crime or help prove what happened.

Direct evidence

Evidence that directly establishes a fact in dispute.

Indirect (circumstantial) evidence

Evidence that suggests a fact without directly proving it.

Testimonial evidence

A person's verbal statement under oath.

Trace evidence

Small material transferred through contact between surfaces.

Demonstrative evidence

Material used to explain or clarify an issue.

Corpus delicti

Evidence establishing that a crime occurred.

Associative evidence

Evidence linking a suspect to a crime.

Chain of custody

Documentation of who handled evidence and how it was safeguarded.

Why mark and package evidence?

To identify it and prevent contamination, damage, or tampering.

Modus operandi (MO)

A person's method of committing a crime.

BOLO

Be on the lookout; a police broadcast sharing identifying information.

Latent fingerprint

A fingerprint transferred onto a surface, often requiring development.

What is DNA used for in investigations?

Comparing biological evidence to help identify or exclude individuals.

How many chromosome pairs do humans have?

23 pairs.

How are identical twins different in DNA identification?

They are the exception to the notes' rule that individuals have unique DNA.

Trace evidence unit

Identifies and compares transferred materials.

Questioned documents unit

Examines handwriting, typewriting, and other document evidence.

DNA analysis unit

Analyzes bodily fluids and stains recovered as evidence.

Forensic photography unit

Handles imaging operations for investigations.

Forensic toxicology

Analyzes biological specimens or food for toxic substances.

Forensic ballistics

Examines firearms, ammunition, firearm components, and tool marks.

Fingerprint science

Uses fingerprints to help identify suspects.

Superglue fuming

Uses cyanoacrylate to develop latent prints on many hard surfaces.

Simultaneous lineup

Shows all lineup members or photographs at once.

Sequential lineup

Presents lineup members or photographs one at a time.

Photo lineup guidelines

Use at least six similar photographs; remove identifying information.

Physical lineup guidelines

Use five or six people with similar characteristics; do not praise selections.

Show-up

A procedure presenting a suspect individually; it can be suggestive.

Factors affecting lineup reliability

Viewing opportunity, attention, description accuracy, certainty, time delay, and witness type.

Fourth Amendment

Protects against unreasonable searches and seizures.

Fifth Amendment

Protects against compelled self-incrimination.

Sixth Amendment

Provides rights including counsel and confrontation.

Due process

Fair legal procedures and protection of legal rights.

Probable cause

Facts supporting a fair probability that a crime occurred or a person committed it.

Reasonable suspicion

A lower level of suspicion than probable cause, based on specific facts.

Exclusionary rule

Generally prevents illegally obtained evidence from being used in court.

Fruit of the poisonous tree

Evidence derived from illegally obtained evidence.

Good-faith exception

Evidence may be admitted when officers reasonably rely on a warrant believed valid.

Inevitable discovery exception

Evidence may be admitted if it would inevitably have been lawfully discovered.

Search warrant affidavit

Explains what is sought, where to search, and why probable cause exists.

Search warrant return

Records the officer, service date, seized property, owner, and required signatures.

Four warrantless search categories in the notes

Consent, exigent circumstances, searches incident to arrest, and stop-and-frisk searches.

Consent search

Search based on knowing and voluntary consent.

Exigent circumstances

Urgent circumstances, such as danger to life or evidence removal, that may justify action without a warrant.

Plain-view exception

Evidence may be seized when officers are lawfully present and legal requirements are met.

Search incident to arrest

A search associated with a lawful arrest.

Terry stop

A brief investigative detention based on reasonable suspicion.

Pat-down search

A limited frisk of a suspect's outer clothing for weapons.

Does a stop automatically permit a pat-down?

No; additional legal grounds are needed.

Arrest, according to class notes

Probable cause plus custody.

Use-of-force factors

Severity of crime, immediate threat, and whether the person resists.

Interview

A formal, nonaccusatory conversation to obtain information.

Interrogation

Systematic, accusatory questioning of a suspect.

Main interview goals

Learn what happened, gather information, and obtain useful details.

Who, what, where, when, why, and how

Core questions used to investigate an event.

Effective interview techniques

Plan, build rapport, listen, ask questions, take notes, and maintain control.

Logical interrogation style

Appeals to logic and possible benefits of cooperation.

Sympathetic interrogation style

Appeals to emotions by expressing concern and understanding.

Indifferent interrogation style

Acts unconcerned about whether the suspect cooperates.

Face-saving interrogation style

Offers the suspect an explanation to justify involvement.

Egotistical interrogation style

Appeals to the suspect's pride or desire to brag.

Miranda rule trigger, according to notes

Custody plus interrogation.

Written statement requirements

Identify the maker, include place and date, use a narrative, and obtain the suspect's signature.

Recorded statement essentials

Identify people present and state the location, time, and date.

Criminal intelligence

Collected and evaluated information used for rational decisions about criminal activity.

Criminal investigation function

Reactive; uses deductive logic and open case files.

Criminal intelligence function

Proactive; uses inductive logic and separately maintained files.

Overt intelligence collection

Open information gathering through interactions with people and documented contacts.

Covert intelligence collection

Discreet gathering using surveillance, informants, or undercover officers.

Data collection matrix

Organizes people and their associations to analyze relationships.

RISS projects

A network of six regional centers supporting information sharing and multijurisdictional investigations.

License plate readers

High-speed cameras that record plates and store the information.

Facial recognition

Uses facial measurements to create a numerical faceprint for identification.

GPS surveillance

Uses satellite-based location information to track movement.

Cell phone tracking

Can locate a powered-on phone using network methods or GPS.

Informant

Person who provides information or intelligence to investigators.

Six informant motivations

Fear, money, revenge, ego, personal motives, and reformation.

Questions for evaluating informants

Motivation, past reliability, knowledge source, personal interest, withheld information, and willingness to testify.

Jailhouse informant risk

May lie or fabricate statements in exchange for leniency.

Aguilar-Spinelli test

Examines an informant's credibility and basis of knowledge.