CSCI 130 Forensic Computing CJ Notes Structure and Conduct of Investigations

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CSCI 130Forensic ComputingCJ NotesStructure
and Conduct of Investigations
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• I. Types of investigations
• a. Reactive action taken after a crime has been
  reported
• b. Proactive action taken to prevent a crime,
  to prevent further crimes, to stop on-going
  criminal activity

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• II. Reactive Investigations
• a. Involve discovery of offense, preliminary
  investigation, and follow-up investigation
• b. How activities structured varies by agency
  some activities are more structured in some
  agencies, as in large agencies

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• III. Preliminary investigation
• a. Often done by responding patrol officer who
  reports findings to investigators
• b. Serious cases will see investigators doing
  preliminary as well as follow-up
• c. Involves such tasks as preserving scene
  identifying evidence and witnesses

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• IV. Follow-Up Investigation
• a. Agency policy determines extent and nature of
  follow-up
• b. Solvability factors play important role
• 1. any evidence that will lead to or is likely
  to contribute to identifying the suspect or
  substantially increases the chances of doing so
• 2. witnesses who can identify suspect

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• 3. witnesses who can provide license plate
  vehicle description
• 4. fingerprints DNA sources blood body
  fluids shoe prints discarded or torn clothing
• 5. other evidence that can identify the suspect

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• c. Detectives perform many duties between arrest
  and court
• 1. re-interview witnesses
• 2. collect additional evidence
• 3. attend to the victim victims family

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• 4. attend meetings with prosecutor supervisors
  for updates
• 5. assist/meet with area agencies re similar
  offenses
• 6. other duties directed toward successful
  prosecution

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• V. Investigators must have a working knowledge
  of law
• a. Search and seizure
• b. Confessions statements
• c. Rules of evidence

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Types of Evidence

• A. Real - physical details and objects, such as
  murder weapon, stolen property, fingerprints, DNA
• 1. May be original objects or facsimile
  representations, such as photographs, casts of
  tire tracks, footprints, or other duplicates of
  unavailable/unusable items in their original form

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• B. Testimonial the sworn, verbal statements of
  witnesses
• 1. All real evidence is accompanied by
  testimonial evidence given by one qualified to
  discuss it
• 2. Not all testimonial evidence is accompanied
  by real evidence, however

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• C. Direct evidence eyewitness evidence
• 1. Testimony from a witness that she saw a
  person painting a fence is direct evidence
• 2. Testimony from a witness as to what he
  heard gunshots, threats made

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• D. Circumstantial also called indirect
  evidence
• 1. Evidence from which a fact can reasonably be
  inferred
• 2. A person was seen carrying a paint can and
  brush one block from a newly painted fence
• 3. Circumstantial evidence that the person
  painted the fence.

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• d. Probable cause for the arrest (Facts or
  circumstances that would lead a reasonable and
  prudent person to believe a crime has been
  committed and the suspect committed it) is a
  lower level of proof than that needed for
  conviction (Proof beyond a reasonable doubt)

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• VI. Factors that influence whether a crime will
  be solved include
• a. Timeliness of initial police response
• b. Collection of evidence
• c. Delay in reporting crime

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• d. Investigator(s) competence agency resources
• e. Competence and cooperation of patrol officers
• f. Complexity of the case

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• VII. Factors that militate against convictions
• a. Lack of evidence, not present or overlooked
• b. Poor presentation of case
• c. Poor case preparation

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• d. Jury nullification
• e. Non-sympathetic victim resulting in weak case
• f. Jury assessment of victim culpability

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• VIII. Information and Evidence
• a. Information is the lifeblood of any
  investigative effort.
• b. All evidence is information but not all
  information is evidence.

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Conclusion

• IX. The work is seldom done
• a. New evidence
• b. New witnesses
• c. Re-visit evidence witness statements