1. Class Name, Instructor Name
Lasley & Guskos, Criminal Investigation: An Illustrated Case Study Approach 1ed
Chapter 2
INVESTIGATORS, INVESTIGATIONS, AND THE LAW
Class Name, Instructor Name
Date, Semester

2. CHAPTER OBJECTIVES
Understand how a crime is legally established by a criminal investigation
Summarize the legal guidelines that police must follow for searches, seizures, and arrests
Describe the process of obtaining and executing a search warrant
Explain when warrantless searches are authorized
Define the term exclusionary rule and its relationship to illegal searches and seizures
Outline the necessary investigative requirements for building a case for prosecution

3. Learning Objectives
After this lecture, you should be able to complete the following Learning Outcomes
Understand how a crime is legally established by a criminal investigation

4. Substantive Criminal laws: Criminal Procedural laws:
Legal requirements that must be met to determine if a crime has been committed and if suspect is guilty or innocent
Criminal Procedural laws:
Laws governing proper procedures for investigators in arrest, search, and seizure
vs. 4 4

5. Body of the crime, investigators must prove a crime has been committed
Establishment of a Crime
Corpus Delecti
Body of the crime, investigators must prove a crime has been committed
Elements of a Crime
Factual elements demonstrated and supported by evidence obtained during the investigation statutes
Actus Reus
The act requirement—performing the act or failing to act when required to do so
Mens Rea
Suspect’s mental state during the act, strict liability for traffic offenses 5 5

6. Learning Objectives
After this lecture, you should be able to complete the following Learning Outcomes
Summarize the legal guidelines that police must follow for searches, seizures, and arrests

7. Search and Seizures

8. Reasonable Suspicion:
Evidence to prove a crime
Reasonable Suspicion:
When a situation would lead an officer to SUSPECT that a crime is being committed, has been committed, or about to be committed
Probable Cause:
An officer’s belief that a crime is being committed, about to be committed, or has already taken place
vs. 8 8

9. Reasonable Suspicion

10. Describe the process of obtaining and executing a search warrant
Learning Objectives
After this lecture, you should be able to complete the following Learning Outcomes
Describe the process of obtaining and executing a search warrant

11. Obtaining Warrant

12. 4th Amendment Search Warrants
Statement of
Probable
Cause
Affidavit-
Written portion
of the warrant
Annotation of
what the officer
wants to search
or locate
Person, place,
thing to be
Knock Warrant
No Knock
Warrant
Search
Warrant
Return
What was
Seized? 12 12

13. Other types of searches
Anticipatory searches—U.S. v. Grubbs, know the date/time of criminal evidence
Sneak and Peak—enter private property without occupants knowing 13 13

14. Explain when warrantless searches are authorized
Learning Objectives
After this lecture, you should be able to complete the following Learning Outcomes
Explain when warrantless searches are authorized

15. Warrantless Search

16. Warrantless Searches Voluntary Consent Exigent Circumstances
consent to search forms, burden of proof on officer
Exigent Circumstances
Threats of harm, imminent threat, destruction of evidence, etc.
Stop-and-frisk searches
Pat down of a person for concealed weapons
Plain feel—officer must show through knowledge, training, and experience that they know what the item “could” be
Plain view—where observation of evidence took place

17. Warrantless Searches Search incident to arrest Special circumstances
Officer safety justification, prevent escape, prevent destruction of evidence
Special circumstances
Open fields doctrine
Abandoned property
Probation/parole searches
School searches
Patriot Act searches

18. Learning Objectives
After this lecture, you should be able to complete the following Learning Outcomes
Define the term exclusionary rule and its relationship to illegal searches and seizures

19. Illegal Search Exceptions
Illegal Searches
Exclusionary Rule—enforce Fourth Amendment and protect citizens from law enforcement
Fruit of the Poisonous Tree Doctrine—extended legal restrictions imposed by exclusionary rule
Inevitable Discovery—evidence would have been discovered as a result of a search
Good Faith Exception—the officer conducting the search was acting in good faith
Illegal Search Exceptions

20. Learning Objectives
After this lecture, you should be able to complete the following Learning Outcomes
Outline the necessary investigative requirements for building a case for prosecution

21. Stages of Case Processing
Identifying and Arresting Suspects
Consensual Encounter:
Casual, nonthreatening, conversations with officers
Detention: when investigators words or actions have them feel they cannot leave
Arrest:
Act of taking an adult or juvenile into custody
Arrest Warrant: probable cause for the arrest 21

22. Stages of Case Processing
Beyond a Reasonable Doubt
Trier of Law
Trier of Fact
Bench Hearing

23. Forms of Evidence Physical or Real Evidence: visible and microscopic
Documentary Evidence: written, printed, reported, or recorded
Testimonial Evidence: spoken words as well as behaviors associated with the words

24. Factual Evidence Factual Evidence Direct: Proves suspects guilt
Circumstantial:
Indirect proof of suspect’s guilt
Corroborative:
Validity & reliability of other evidence
Cumulative:
Adds strength to other evidence

25. CHAPTER SUMMARY
Evidence must suggest that a crime has been committed—the corpus delicti of the crime. Sufficient evidence must be presented that satisfies the specific elements of a particular criminal activity proved within written codes or statutes. For most crimes that are the subject of investigation, a physical act as well as a criminal state of mind at the time of the act must be demonstrated by available evidence.
Reasonable suspicion and/or probable cause must be present to conduct a search and/or seizure. Officers must follow the Fourth Amendment in this area.
Probable cause is the necessary standard for conducting most searches and carrying out arrests.
The Supreme Court has authorized warrantless searches and seizures in situations involving potential medical emergencies, threats to officers’ safety, and the preservation of public safety.

26. CHAPTER SUMMARY
The exclusionary rule states that evidence searched for and/or seized through illegal methods and means is inadmissible (or not allowable) in a court of law. This rule has been extended through the fruit of the poisonous tree doctrine to prohibit from court proceedings all evidence proven to have originated from an illegal search.
For investigators building a case for successful prosecution, the primary goal is to gather evidence to prove beyond a reasonable doubt that a particular suspect has committed a specific crime. Investigators can rely on physical or “real” evidence, documentary evidence, and testimonial evidence to build their case. These forms of evidence can be presented in the form of direct evidence (directly proving the guilt of a suspect) or indirect evidence (indirectly proving the guilt of
a suspect).