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Criminal Procedure: Investigation
St. Louis University School of Law
Miller, Eric J.

Criminal Procedure: Investigation
Prof. Miller, Spring 2009

1. Arrest, Probable Cause, and Warrants
a. General Principles
i. Fourth 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 Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.
ii. Applicable to both searches and arrests:
1. The Fourth Amendment applies both to searches and seizures of property and to arrests of persons. Most Fourth Amendment problems relate to the constitutional legality of searches, not arrests.
2. Way in which litigation arises
a. A search is conducted, and evidence is seized. After the suspect is arrested, he seeks to show, at a suppression hearing, that the search was conducted in violation of the Fourth Amendment. If he can show this, then the evidence which was obtained as a result of the search will not be admissible at trial, in either the federal or state courts. Mapp v. Ohio (1961).
3. Invalid arrest no defense
a. Except in a very few cases of shocking and violent police conduct, a defendant may be tried and convicted regardless of the fact that his arrest was made in violation of the Fourth Amendment.
b. Importance of valid arrest
i. Although a search is not usually valid unless a search warrant is obtained, no warrant is required for a search made “incident” to a valid arrest. When evidence is seized as part of a warrantless search conducted incident to an arrest, the defendant will therefore frequently argue that the arrest itself violated the Fourth Amendment, that the search was thus invalid, and that the evidence obtained from it is inadmissible under Mapp v. Ohio.
iii. Two clauses of Fourth Amendment
1. The Fourth Amendment applies both to situations in which a warrant is used and to those in which no warrant is procured.
a. If a warrant is used, the Amendment requires that it not be issued unless there is “probable cause.”
b. Whether or not there is a warrant, the Amendment requires that the arrest or search not be “unreasonable.”
b. Areas Protected by the Fourth Amendment
i. Protected places approach
1. Until 1967, courts viewed the Fourth Amendment as protecting certain places, almost always limited to private property owned by the subject of the search. The courts did not utilize any subjective concept of privacy.
2. Curtilage concept
a. This traditional approach gave Fourth Amendment protection not only to houses, but also to the area surrounding a dwelling, known as the curtilage of the dwelling. The curtilage consisted of all buildings in close proximity to a dwelling, which are continually used for carrying on domestic employment, or such place as is necessary and convenient to a dwelling, and is habitually used for family purposes. US v. Potts (6th Cir. 1961).
ii. Katz and the “reasonable expectation of privacy” doctrine
1. In 1967, the Court rejected the traditional notion that only private property could be protected by the Fourth Amendment, and that the curtilage concept was the correct way to determine the Fourth amendment’s applicability. Instead, the Court indicated that the Fourth Amendment applies to any government search or seizure that interferes with a per

i. The Court held that although a passenger clearly expects that his bag may be handled, he does not expect that other passengers or bus employees will, as a matter of course, feel the bag in an exploratory manner. The exploratory squeezing by the government agents here went beyond what D reasonably expected, and therefore invaded his reasonable expectation of privacy.
c. Significance of trespass:
i. Bond is significant because it illustrates the significance of a physical intrusion (i.e. a trespass).
ii. Court held that physically invasive inspection is simply more intrusive than purely visual inspection (thus, Bond is different than Ciraolo and Riley, in which the Court had held that police observation from an overflying aircraft did not violate the defendant’s reasonable expectation of privacy).
iii. Presence of trespass is not dispositive.
1. But, the fact that there has been some kind of physical intrusion or trespass by government agents does not automatically mean that there was a Fourth Amendment search or seizure.
a. U.S. v. Dunn: Drug agents trespassed onto D’s ranch in order to peer into D’s barn, but because the barn was not within the curtilage of the farmhouse, D was found to have no justifiable expectation of privacy with respect to the barn and no Fourth amendment search was found to have taken place.