Criminal Investigation:
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
Key Definitions:
Investigate - derived from Latin, vestigare ( to track or trace )
Criminal investigation – discovering, collecting, preparing, identifying and presenting evidence
Deductive reasoning – logical process; conclusion follows from specific facts
Terms: Criminalist, Forensic science, Crime, Felony, Misdemeanor
Criminal statute, Ordinance, Elements of the crime, Criminal intent, Modus operandi or MO,
Goals of Criminal investigations
Successful Investigation
- 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 te prosecutor
Basic Functions of Investigators
- Provide emergency assistance
- Secure the crime scene
- Photograph, videotape and sketch
- Take notes and write reports
- Search for, obtain and process physical evidences
- Obtain inforamtion from witnesses and suspects
- Identify suspects
- Conduct raids, surveillances, stakeouts and undercover assignments
- Testify in court
Characteristics of an Effective Investigator
Specific Character traits - intellectual, psychological and physical
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 indiciduals
The Preliminary Investigation: Basic Considerations
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
Point of Arrival
Scene may be either utter confusion or deserted
Setting Prorities
Handle emergencies first
Secure the scene
Investigate
Handling Emergency Situations
Sometimes emergencies dictate procedure
Emergency situations cause the adrenaline to flow
Suspect at or Near the Scene
Policy determines interrogations
Miranda warning
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
Protecting the Crime Scene
Major responsibility of the first officers to arrive
Locards’s principle of exchange
Scene is critical
Maintain security
Protect from destruction or alteration from the elements
Conducting the Preliminary Investigation
Questioning
Neighborhood canvass
Measuring, photographing, videotaping and sketching
Searching for evidence
Processing physical evidence
Recording all statements
Crime Scene Investigators:
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
The Follow-Up Investigation
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
Computer-Aided 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
Problem-Oriented Policing
Department-Wide Strategy
- Aimed at solving persisitent community problems
- Identify, analyze and respond
- Used in crimnal investigations in many ways
- Combining prob;em-oriented strategies with traditional investigative techniques
Investigative Productivity
Productivity
- Interest in the police field for some time
- All jobs have some standard of productivity
- Traditional evaluation ( Number of cases assigned and type of case assigned )
- Continuous evaluation
The Investigative Function: the Responsibility of All Police Personnel
Specialization Need:
- Criminals and their MOs
- Investigative techniques
- Leaving assigned shifts
- Heavy patrol workloads
- Increasing efficiency
Interrelationships with Others – Community Policing
Community Policing Relationships
- Uniformed patrol, dispatchers, prosecutors
- Physicians, coroners and medical examiners
- Forensic crime laboratories
- Citizens, victims, witnesses, media
Major-Case task Forces
Combined task Forces
- Necessary for many crimes involving drugs, gangs and terrorism
- Multidisciplinary approach
- Multijurisdictional investigation
- Metro crime teams
- Special investigation units
Law Enforcement Resources
Federal law Enforcement
- Numerous resources
- Aid local and state agencies
Interpol
- International Criminal Police Organizations
- Computerized database is available to law enforcement agencies worldwide
Avoiding Civil Liability
Civil Liability
- Effective policies and procedures clearly communicated to all
- Thorough and continous training
- Poper supervision and discipline
- Accurate, thorough police reports
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 invvestigation is, indeed, a mutual effort
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