Transcript CHAPTER 3 (48)

CHAPTER 3 (48)
THE INVESTIGATIVE
METHOD
STARTING POINTS
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1. State the problem
2. Form the hypothesis
3. Observe and experiment
4. Interpret the data
5. Draw conclusions
INVESTIGATIVE ACTIONS
STATE THE PROBLEM
Who, what, when, where, why, how
FORM THE HYPOTHESIS
Establish Motive, Means, Opportunity
OBSERVE AND EXPERIMENT
Evaluate hypothesis, reject if needed
Interpret results
Identify suspect
INVESTIGATIVE ACTIONS (Cont.)
• DRAW CONCLUSIONS
Stated problem answered
Evidence support of hypothesis
Ethics considerations
Evidence adequate for prosecution
EFFECT ARREST, RECOVER
PROPERTY
EVIDENCE/HYPOTHESIS
• ALWAYS LET YOUR EVIDENCE DEIVE
YOUR HYPOTHESIS!!!!!
• YOUR HYPOTHESIS MUST CHANGE
• WHEN EVIDENCE SUPPORTS THE
• CHANGE!!!!!
• THE HYPOTHESIS MUST NEVER DRIVE
THE INVESTIGATION!!!!!
HYPOTHESIS
• Construct an explanation for occurrence
Why this type and particular target?
How knew locations of valuables?
WHO HAD MOTIVE, MEANS , AND
OPPORTUNITY?
MOTIVE
• That which causes a person to act in a
certain way.
• Monetary gain is the most likely.
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Murder: Ask who would benefit.
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Arson: Ask who would benefit.
MEANS
• Capability of committing the crime
• Who has the tools?
• Who has the knowledge?
OPPORTUNITY
• Who was present that could have
committed the crime?
• What was the victim doing that could have
put him/her into contact with the offender?
Suspect out of town or in jail
Suspect has an alibi
OTHER PHASES
• Observation and experimentation
• Testing hypotheses
• Interpreting data
ALL THESE ARE SIMULTANEOUSLY WITH
THE OTHER PHASES
PUZZLE-Number of pieces? Lack of pieces?
Final picture?
GUILTY OR NOT
• Inculpatory evidence serves to prove guilt
• Exculpatory evidence clears or exonerates
LEGAL GUIDELINES
• Evidence- Anything properly admissible in
court that will aid the function of a criminal
proceeding in establishing guilt.
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Admissible means that it can be legally
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used in court.
Inadmissible means that it cannot be legally
used in court
CIRCUMSTANTIAL
• The more physical evidence the better.
– You never have all you need
– If there is anything else, get it.
TYPES OF EVIDENCE
• DIRECT EVIDENCE
Will normally prove a fact without other
support. Testimonial
INDIRECT EVIDENCE
All physical evidence is CIRCUMSTANTIAL.
It puts the suspect at the crime scene.
It does not prove guilt in itself.
PHYSICAL EVIDENCE
• Real evidence, physical, tangible items
• May be trace evidence- forensic, needs
analysis
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Fingerprints
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Hairs
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Fibers
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Blood
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DNA- Deoxyribonucleic acid
SUITABILITY
• EVIDENCE MUSTBE COMPETENT
• Has qualities that make it trustworthy or
reliable. Question who is reliable?
• RELEVANT
• Relates directly to the case
• MATERIAL
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Logical connection and helps find truth
EXCLUSIONARY RULE
• Illegally obtained evidence cannot be used
in court. Applies to violations of
Constitutional rights
Weeks v. US
Mapp v. Ohio
EXCEPTIONS
• HEARSAY
• Confessions to an investigator
• Dying declarations
• Res Gestae statements
• Judicial notice
• Testimony of a female under 14 yr. who is
a victim of a sex crime
RULE OF DISCOVERY
• Allows the defendant, through his attorney,
to examined documents, reports and other
information in possession of the police or
prosecution
• Prosecution must give up everything
• Lose your case in a suppression hearing
PROBABLE CAUSE
• 4th Amendment
• ARREST- A reasonable person would
believe that a crime has or will be
committed and the person to be arrested
committed or will commit the crime.
• SEARCH- A reasonable person would
believe that a crime has or will be
committed and evidence of the crime will
be found in the place to be searched
SEARCH WARRANT
THREE PARTS
AFFIDAVIT
WARRANT
RETURN
EXCEPTIONS
• REQUIRES SAME PROBABLE CAUSE
• WARRANTLESS SEARCH IS
UNCONSTITUTIONAL ON ITS FACE
EXCEPTIONS
• Exigent
circumstances
• Stop and frisk
• Search incident to
arrest
• Custodial
• Plain view
• Vehicle
• Border
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Open fields
Abandoned property
Consent
Administrative
Probation search
Protective sweep
BURDEN OF PROOF
• CRIMINAL CASE- Beyond a reasonable
doubt- continuous demonstration of guilt
• 99+ percent sure
• CIVIL CASE- A preponderance of the
evidence- whoever has the best case
• 50+ percent sure
CORPUS DELICTI
• “BODY OF THE CRIME”- The fact
necessary to prove that a crime was
committed.
• All the essential ELEMENTS of an offense
constitute the “corpus delicti”
• Investigator must know all the elements of
every crime and be able to prove each
beyond a reasonable doubt
PHASES OF CRIMINAL
INVESTIGATION
• PRELIMINARY INVESTIGATION
• IN-DEPTH INVESTIGATION
• CONCLUDING INVESTIGATION
PRELIMINARY
• Offense determined
• Basic statements
taken
• Suspect arrest if he is
on scene
• Crime scene
processed- by
• Protect crime scene
investigator
• Victims and witnesses
identified
IN-DEPTH INVESTIGATION
• Preliminary inv. Data
re-examined
• Crime scene revisited
• Additional crime
scene processedMay need to get
another search
warrant
• All victims and
witnesses interviewed
• Documents
processed
• Facts and evidence
gathered
• Criminalistics
arranged- forensic
work
CONCLUDING INVESTIGATION
• Case is suspended
• Case is prepared for prosecution
CLEARANCE RATES
• VIOLENT CRIMES
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Murder
Aggravated assault
Forcible Rape
Robbery
61%
54%
41%
25%
CLEARANCE RATES
• PROPERTY CRIMES
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Burglary
Larceny-theft
Motor vehicle theft
Arson
13%
17%
13%
17%
SUCCESSFUL INVESTIGATIONS
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1. Are there witnesses?
2. Is there a suspect?
3. Can police locate the suspect?
4. Is there a description (photo)?
5. Can police make identification?
6. Can a suspect vehicle be identified?
7. Is stolen property traceable?
SUCCESSFUL INVESTIGATION
• 8. Is there a clear modus operandi (MO)?
• 9. Is there significant physical evidence?
• 10. Is there a positive report of physical
evidence by a trained investigator?
• 11. Is it reasonable to expect the case to
be cleared?
• 12. Is it likely that anyone but the suspect
committed the crime?
IN-DEPTH/ CONCLUDING
INVESTIGATION
• SEE P. 62 IN TEXT FOR ACTIVITIES OF
THE IN-DEPTH INVESTIGATION
• SEE P. 63 IN TEXT FOR ACTIVITIES OF
THE CONCLUDING INVESTIGATION
ARREST/ PROSECUTION
• SEE P.64 FOR THE TYPICAL OUTCOME
OF 100 FELONY CRIME
INVESTIGATIONS
SEARCH WARRANT
• SEE SEARCH WARRANT EXAMPLE