Investigators, the Investigative Process, and the Crime Scene

Chapter Objectives

Understand the skills and qualities needed by investigators.

Identify the objectives of crime scene investigation.

Distinguish between the preliminary and follow-up investigations.

Explain the importance of crime scene coordination.

Explain the factors that may affect crime scene processing plans.

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Chapter Objectives

Discuss three broad categories of evidence.

Explain the “rules” for crime scene investigators.

Identify crime scene health issues. Summarize the four major

considerations that dominate the crime scene search.

Identify different methods of visually documenting the crime scene.

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What Is A Crime?

A crime is the commission or omission of any act, which is prohibited or required by the penal code of an organized political state, to which some punishment or sanction is attached.

Classifications Felony

Punishable by death or imprisonment for more than one year in a state prison.

Misdemeanor Punishable by fine and/or imprisonment for up to one

year in a local or county jail. Infraction or Violation

Minor offenses punishable by a fine only.

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The Investigator

Someone who gathers, documents and evaluates evidence. Strong professional training and experience Strong degree of self-discipline Uses legally approved & ethical methods Does not act out of malice or bias Includes all evidence of innocence as well as guilt Uses systematic methods of inquiry Uses both inductive and deductive reasoning Compassionate, not calloused and cynical Has wide ranging contacts across many

occupations Remains objective at all times Leaves nothing to chance during investigation

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The Investigative Process Objectives

Establish if a crime was committed

Collect, document and preserve evidence

Identify and apprehend the suspect(s)

Recover stolen property Assist in the prosecution of

the person(s) charged with the crime(s) Major events in the

investigation of a crime

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The Preliminary Investigation The actions taken at the scene of a

crime immediately following its detection and report to the police Receipt of information and initial

response Emergency care Crime scene control BOLO alerts Crime scene determination Evidence The report

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Follow-up Investigation

Subsequent investigation Contacting witnesses who left the scene Checking out suspect(s) alibi Gathering additional evidence from other

locations Talk with informants Attempt to locate additional witnesses Evaluate evidence collected and laboratory

results of tests Obtain search and/or arrest warrants Recover stolen property Confer with prosecutor

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Crime Scene

Location where the offense was committed May include surrounding areas where

evidence may be located Always start big . . . It’s much easier to

make it smaller than to expand it at a later time

There may be more than one crime scene

Macroscopic versus Microscopic scenes

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Crime Scene continued

Crime-scene investigators examine blood-stained clothes before placing them in an evidence bag.

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Rules for the Crime Scene Investigation Note all dispatch information Be alert for people and cars leaving the crime

scene or its immediate proximity and note their numbers and descriptions

Approach the scene with caution Determine whether a tactical situation exists Remain alert and attentive Make sure that you follow departmental contact

protocols Treat the location as a crime scene until you

conclude otherwise If suspect is still at the scene, arrest him/her Officer’s field notes should include information

about a variety of conditions11© 2012 McGraw-Hill Higher Education. All rights reserved.

Organization Of The Crime Scene Overall coordination

Handled by assigned case agent Power to call in additional resources &

coordinate all investigative activities Technical services

Crime laboratory personnel & supervisors Investigative services

Interviewing witnesses and victims Neighborhood canvass Suspect field interrogations

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Categories Of Evidence

Corpus Delicti evidence Evidence that helps to prove the elements

of the crime(s)

Associative evidence Evidence that connects the suspect to the

scene and/or victim or connects the scene/victim to the suspect It is bidirectional

Trace evidence Small or microscopic evidence, or evidence

in limited amounts13© 2012 McGraw-Hill Higher Education. All rights reserved.

Evidence Recovery Log

A chronological record of who found what evidence, where, witnessed by whom, and notations about other ways the evidence may have been documented, e.g., photography

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Evidence Recovery Log

The evidence recovery log is an important document which records all pieces of physical evidence found at a crime

scene. This is critical if the case is to be successfully prosecuted later.

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Crime Scene Control

The actions which the first arriving officer at the crime scene takes to make sure that the integrity of the scene is maintained.

Control also includes preventing people at the scene from becoming combatants and separating witnesses.

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Conceptualization

Keep known facts AND inferences in mind when processing scene Facilitates reconstruction of the offense Identification of the modus operandi Identification of certain types of

evidence Assists in establishing investigative

direction

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Caution

Don’t destroy evidence Make crime scene bigger than

expected and shrink as necessary Don’t overlook fruitful areas for

exploration Do more than a cursory examination

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Inclusiveness

Obtain every piece of evidence If not sure, take it as evidence until it

is ruled out Do not dismiss items of possible

evidence Be careful of rationalization and fatigue

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Documentation

Constant Activity Starts with rough shorthand field notes Sketches Diagrams to scale

WAYS TO DOCUMENT A CRIME SCENE VISUALLY INCLUDE: Video taping Photographing Sketching

(Courtesy Lewiston, Maine, Police Department)20© 2012 McGraw-Hill Higher Education. All rights reserved.

Threats To Investigators Health And Safety At Crime Scenes Insect bites HIV/AIDS Hepatitis B and C Tuberculosis

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Major Considerations Of The Crime Scene Search Boundary Determination Choice of Search Patterns Instruction of Personnel Coordination Documentation

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Crime Scene Search PatternsThe crime scene coordinator may choose from a

variety of crime scene search patterns based upon the type and size of the crime scene.

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Digital Video Recording

Keep the lens clean Use battery packs instead of cords Begin recording with an identification Keep camera running once recording

begins Pan the crime scene area 360 degrees Use a rolling tripod or should brace for

smoother pictures Don’t go too fast

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Digital Still Photography Four classes of photographs that

must be taken with digital still cameras: Orientation Relationship Identification Comparison

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Crime Scene Sketching and Forensic Mapping Crime scene sketch

Rough sketches: made by hand at the scene

Smooth or finished sketches: drawn at the office—either by hand or by specialized computer software

Forensic mapping Overhead or bird’s-eye view Elevation view Cross-projection view

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Submitting Evidence to the Crime Laboratory The investigator’s name, agency, address,

telephone number, and email address. Copies of any previous correspondence about

the case, including any pertaining to other evidence that was examined earlier.

The type of criminal act and the basic case facts related to each item of evidence.

The name(s) and descriptive data about the individual(s) involved (subject, suspect, victim, or a combination of those categories) and the agency assigned case number.

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Submitting Evidence to the Crime Laboratory A list of the evidence being submitted. What type(s) of examination is requested. Where the evidence should be returned and

where the laboratory report should be sent. A statement if the evidence was examined

by another expert in the same field, if there is local controversy, or if other law-enforcement agencies have an interest in the case.

Any reason(s) justifying an expeditious examination request.

The name and locator information for the assigned prosecutor, if designated already.

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Investigative Success

Law enforcement considers a case successful if it can be administratively classified: “Cleared by exceptional means” “Cleared by arrest”

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