criminal investigation

Criminal Investigation

The Study of facts to understand motives, identify criminals, and the sequences leading to a trial to reach a verdict

Primary Goals of Criminal Investigation

To collect the facts so a verdict can be reached

Basic Functions performed by investigators

Provide emergency assistance, secure the crime scene, photograph, videotape, and sketch the scene, take notes and write reports, search and obtain physical evidence

Key aspects of the initial investigation

The initial response, setting priorities, handle emergencies, secure the scene, investigate

Probable Cause

Facts and circumstances are sufficient in themselves to warrant a person of reasonable caution to believe that a crime has been or is being committed

Totality of Circumstances

Legal method of analysis where a judge or court take into account of all the facts and context of a case

Locards Exchange Principal

Wherever you go leaves evidence, all contact leaves a trace

Modus Operandi

Characteristics of a criminals method of operation, how someone does something

Res Gestae

Exception to the role of hearsay evidence

Hearsay

Can’t being outside statements into the court

How do investigators decide whether or not to pursue a criminal investigation

Must have probable cause, and enough evidence beyond a reasonable doubt

Deductive reasoning

Using general rules or statements to reach a conclusion

Forensic science

Using scientific methods and techniques for investigations by a court of law

Actus Reus

The act of committing the crime

Mens rea

The mental state behind the act

Causation

Actions that cause the outcome

Concurrence

Tying in Actus Reus and Mens rea together

Field notes

Permanent written records of the facts of a case to be used in further investigation, in writing reports and in prosecuting the case

Record all information that helps to answer the questions of

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

When taking notes, the investigator should

Learn to select the key facts and record them in abbreviated form

Photographs should be taken when?

Before anything is disturbed

The amount of notes taken is determined by?

The conditions or severity of each case

Basic purpose of field notes is to?

Record all facts of the incident

Crime scene sketch accomplishes?

Accurately portrays the physical facts, relates the sequences of events at the scene, and establishes the precise location and relationship of objects and evidence at the scene

Types of investigative photography includes?

Crime scene and mug shots, Aerial, night and laboratory pictures, lineup photos and those related to the crime scene

When taking photographs/videotape, the investigator should?

Take sufficient photographs and/or videotape to reconstruct the entire scene

Being concise means to?

Eliminate wordiness

What should be photographed first?

Fragile evidence

Crime scene photographs use?

Weather conditions, services rendered, name, address, phone number of every person present

Crime scene photographs are?

Not a substitute for anything, need both photographs, and sketches

Direction of the top of sketch?

North

Order of photographs taken

General area, specific area, specific objects. Overall, midrange, and closeups

When should I sketch serious crime and crash scenes?

Both after taking photos and before anything is moved

Arrest

Is like a type of of seizure, and like a search, is restricted by the fourth amendment and requires probable cause.

4th amendment

Constitution forbids unreasonable searches and seizures and requires the legal searches and seizures be based on probable cause

Arrest defined

Taking a person into custody for the purpose of presenting that person to answer a crime

De facto arrest

occurs when police officers exceed the scope of a brief investigative detention (a Terry stop) and treat a person in a way that mirrors a formal, full arrest without having official probable cause.

Importance of reports

-considerable time of an officers time is spent writing reports.

-reports used by many different parties in criminal justice

-small details can have a major impact on case disposition

When deciding what to record ask what?

WHO, WHAT, WHERE, WHEN, HOW, WHY?

Timeline of point of arrival

Setting priorities, handle emergencies first, securing the scene, investigate

When at the Initial investigation what occurs?

-Suspect may still be at or near the scene

-injured persons may need emergency care

-witnesses may still be at the scene

-dying persons may have confession/info

Crime scene and evidence MUST BE PERSEVERED