1. Criminal Investigation and the Law
CJUS 201
Part 5

2. The Investigator and the Law
Basis for every officer’s actions
Understand:
- criminal law / criminal procedure / rules of evidence
Criminal Procedure Law
- tools of investigative craft
- used daily
- arrest / search / seizure

3. Levels of Proof Continuum
Understanding levels of proof
- actions legally taken
a. Extremes: “no proof” / “absolute proof”
- not a concern for investigator
Other five levels:
a. Suspicion
- more than no proof
- not enough to justify intrusion

4. Proof, cont. - expectation of privacy - justify opening a case
b. Reasonable suspicion
- justify investigative detention
- “Specific and articulable facts which taken together with rational inferences
from those facts, reasonably warrant that intrusion”

5. Proof, cont. c. Probable cause (4th Amendment)
“The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures shall not be violated, and no warrants shall issue, but upon probable cause, supported by an oath or affirmation, and particularly describing the place to be searched and persons or things to be seized”

6. Proof, cont. - establish by variety of techniques
- personal observation / eyewitness
- informant / physical evidence
d. Preponderance of evidence
“Evidence which is of greater weight or more convincing than evidence offered in
opposition to it”
- fact to be proved
- more probable than not

7. Proof, cont. - of little concern (suppression hearing)
e. Proof beyond a reasonable doubt
- cannot be precisely defined
- standard of a criminal trial
- provide legally available evidence
- firmly convinced of guilt
Types of evidence
- 7 primary types

8. Evidence, cont. a. Direct – eyewitness / DNA / fingerprints
b. Circumstantial – links suspect to crime
c. Real – can see / touch / hold
d. Documentary – writings / printouts
e. Testimonial – oral testimony

9. Evidence, cont. f. Corroborative – facts to support
g. Judicial Notice – common knowledge
Search and seizure
- warrant / plain view / permission
a. Warrant – best method
- defense must show invalid
- defines authority of police

10. Evidence, cont. b. Plain View – observation by officer
- legally at location
c. Permission – search allowed by owner
- prosecution must prove in court