Chapter 1

Criminal Investigation: An Overview

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Introduction• An observant police officer can initiate an important

criminal investigation• Criminal investigation combines art and science • Requires extraordinary preparation and training• High-tech society• Citizens expect results more quickly• Investigators need to step up their technology and

teamwork skills

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HISTORICAL SIGNIFICANCE

• Bow Street Runners• Vidocq Society• Scotland Yard• Pinkerton National

Detective Agency• Major advances in criminal investigation

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A Brief History of Criminal Investigation

KEY DEFINITIONS

• Investigate Derived from Latin, vestigare, meaning to track or trace

• Criminal investigation Discovering, collecting, preparing, identifying and

presenting evidence

• Deductive reasoning Logical process; conclusion follows from specific facts

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Criminal Investigation Definitions

SPECIFIC TERMS

• Criminalist

• Forensic science

• Crime

• Felony

• Misdemeanor

Continued

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Other Terms Defined

SPECIFIC TERMS

• Criminal statute

• Ordinance

• Elements of the crime

• Criminal intent

• Modus operandi, or MO

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Other Terms Defined (Continued)

SUCCESSFUL INVESTIGATIONS

• Determine whether a crime has been committed

• Legally obtain information and evidence to identify the responsible person

• Arrest the suspect

• Recover stolen property

• Present the best possible case to the prosecutor

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Goals of Criminal Investigations

INVESTIGATOR FUNCTIONS

• Provide emergency assistance

• Secure the crime scene

• Photograph, videotape and sketch

• Take notes and write reports

• Search for, obtain and process physical evidence

Continued

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Basic Functions of Investigators

INVESTIGATOR FUNCTIONS

• Obtain information from witnesses and suspects

• Identify suspects

• Conduct raids, surveillances, stakeouts and undercover assignments

• Testify in court

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Basic Functions of Investigators (Continued)

SPECIFIC CHARACTER TRAITS

• Intellectual

• Psychological

• Physical

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Characteristics of an Effective Investigator

INVESTIGATIVE PROCESS

• Usually initiated by personal observation or information from a citizen

• Starts with a direction to proceed to a scene

• Department policy defines who responds

• Department policy defines duties of individuals

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An Overview of the Investigative Process

THE INITIAL RESPONSE• Suspect may still be at or near the scene

• Injured persons may need emergency care

• Witnesses may still be at the scene

• Dying person may have confession/information

• Weather may change/destroy evidence

• Crime scene may be altered

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The Preliminary Investigation: Basic Considerations

POINT OF ARRIVAL• Scene may be either

utter confusion or deserted

SETTING PRIORITIES• Handle emergencies first• Secure the scene• Investigate

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The Preliminary Investigation: Basic Considerations

HANDLING EMERGENCY SITUATIONS• Sometimes emergencies dictate procedure

• Emergency situations causes the adrenaline to flow

SUSPECT AT OR NEAR THE SCENE• Policy determines interrogations

• Miranda warning

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The Preliminary Investigation: Basic Considerations

PERSON IS SERIOUSLY INJURED• Emergency first aid

• Call for medical assistance

• Accompany suspects to hospital

DEAD BODY AT SCENE• Leave the body as found

• Preserve the scene

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The Preliminary Investigation: Basic Considerations

PROTECTING THE CRIME SCENE• Major responsibility of the

first officers to arrive

• Locard’s principle of exchange

• Scene is critical

• Maintain security• Protect from destruction or

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The Preliminary Investigation: Basic Considerations

CONDUCTING THE PRELIMINARY INVESTIGATION• Questioning • Neighborhood canvass• Measuring, photographing,

videotaping and sketching• Searching for evidence• Processing physical evidence• Recording all statements

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The Preliminary Investigation: Basic Considerations

SCIENTIFIC SPECIALIST• Specialist in organized scientific collection and

processing of evidence

• Processes and packages all physical evidence

• Attends and documents autopsies

• Writes reports and testifies in court

• Crime scene technology degree

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Crime Scene Investigators

FACTORS FOR FOLLOW-UP• Many cases require a follow-up investigation

• Factors exist that are beyond the officers’ control

• Weather can destroy evidence

• Witnesses can be uncooperative

• Follow-up phase builds on what was learned

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The Follow-Up Investigation

CRIME ANALYSIS, MAPPING AND GEOGRAPHICAL INFORMATION SYSTEMS• Crime mapping and hot spots

DATA MINING• Sifting through information

• Helps narrow the field of possible suspects

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Computer-Aided Investigation

DEPARTMENT-WIDE STRATEGY• Aimed at solving persistent community problems

• Identify, analyze and respond

• Used in criminal investigations in many ways

• Combining problem-oriented strategies with traditional investigative techniques

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Problem-Oriented Policing

PRODUCTIVITY• Interest in the police field for some time

• All jobs have some standard of productivity

• Traditional evaluation Number of cases assigned Type of case assigned

• Continuous evaluation

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Investigative Productivity

SPECIALIZATION NEED• Criminals and their MOs

• Investigative techniques

• Leaving assigned shifts

• Heavy patrol workloads

• Increasing efficiency

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The Investigative Function: The Responsibility of All Police Personnel

COMMUNITY POLICING RELATIONSHIPS• Uniformed patrol, dispatchers, prosecutors

• Physicians, coroners and medical examiners

• Forensic crime laboratories

• Citizens, victims, witnesses, media

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Interrelationships with Others—Community Policing

COMBINED TASK FORCES• Necessary for many crimes involving drugs, gangs and

terrorism

• Multidisciplinary approach

• Multijurisdictional investigation

• Metro crime teams

• Special investigation units

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Major-Case Task Forces

FEDERAL LAW ENFORCEMENT• Numerous resources• Aid local and state agencies

INTERPOL• International Criminal Police Organization

• Computerized database is available to law enforcement agencies worldwide

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Law Enforcement Resources

CIVIL LIABILITY• Effective policies and procedures clearly

communicated to all

• Thorough and continuous training

• Proper supervision and discipline

• Accurate, thorough police reports

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Avoiding Civil Liability

Summary• Determine whether a crime has been committed• Legally obtain sufficient information and evidence• Locate and arrest the suspect• Recover stolen property• Present the best possible case to the prosecutor• Cooperation and coordination of efforts are also

required outside the police department• Criminal investigation is, indeed, a mutual effort

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