1. Investigators, the Investigative Process, and the Crime Scene
Chapter 3
Investigators, the Investigative Process, and the Crime Scene

2. Learning Objectives
Understand the role of the investigator and skills and qualities they must possess
Discuss major events in the investigation of a crime
Explain the major steps in a preliminary investigation
Describe activities conducted in a follow-up investigation
Define a crime scene
Outline purposes and functions of an investigator

3. Chapter Objectives
Explain the “rules” for the crime scene investigator
Identify potential threats to investigators’ health and safety
Be familiar with major considerations that dominate the crime scene search
Be able to discuss investigation of staged crime scenes
Explain crime scene reconstruction

4. 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.

5. 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

6. 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

7. 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

8. 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

9. 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

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

11. Rules for the Crime Scene Investigation
Maintain Control
Conceptualize Events
Proceed with Caution
Apply Inclusiveness
Maintain Documentation
Chief Charles Moose addresses the news during the Washington D.C. sniper investigation. (©AP/Wide World Photos)

12. 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

13. 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 amounts

14. 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

15. 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.

16. 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.

17. 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

18. 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

19. 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

20. 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)

21. THREATS TO INVESTIGATORS HEALTH AND SAFETY AT CRIME SCENES
Insect bites
HIV/AIDS
Hepatitis B and C
Tuberculosis

22. MAJOR CONSIDERATIONS OF THE CRIME SCENE SEARCH
Boundary Determination
Choice of Search Patterns
Instruction of Personnel
Coordination
Documentation

23. CRIME SCENE SEARCH PATTERNS
The crime scene coordinator may choose from a variety of crime scene search patterns based upon the type and size of the crime scene.

24. Crime Scene
Police diver recovers a handgun as part of an underwater investigation.