crim pro rules

Government Action requirement

The Fourth Amendment applies only to actions taken by government officials or private parties acting as instruments or agents of the government^[1]. Purely private searches do not trigger Fourth Amendment protections unless government encouragement or participation is present^[1]. Scope of Civil Authorities: Under New Jersey v. T.L.O., Fourth Amendment restraints extend to civil state actors, including public school administrators, building inspectors, and fire officials.

Standing to Challenge a Search

To challenge law enforcement conduct under the Fourth Amendment, a claimant must demonstrate a personal, legitimate expectation of privacy in the invaded place or a possessory interest in the property seized^[1][2]. Standing cannot be asserted vicariously based on the violation of a third party’s constitutional rights^[2].

The Katz Expectation of Privacy Test:

A government intrusion constitutes a Fourth Amendment search if the individual exhibits an actual, subjective expectation of privacy, and that expectation is one that society is prepared to recognize as objectively reasonable^[3].

The Jones Physical Trespass Test:

A search also occurs under the Fourth Amendment when the government physically intrudes or trespasses upon a constitutionally protected area—specifically one's person, house, papers, or effects—for the purpose of obtaining information^[3].

Home & Curtilage Protections

The home receives the highest level of Fourth Amendment protection^[3]. This protection extends to the curtilage—the area immediately surrounding and intimately linked to the home^[3]. Proximity to the home, presence within an enclosure surrounding the home, nature of use, and privacy steps dictate whether an area constitutes curtilage rather than an unprotected open field^[3].

Open Fields Doctrine

Unenclosed or exterior property located beyond the home's curtilage does not provide a reasonable expectation of privacy and may be searched without a warrant or probable cause

Sensory Enhancement & Technology

Using sense-enhancing technology not in general public use to explore details of the home that would previously have been unknowable without physical intrusion constitutes a search^[3]. Physical intrusion by narcotics detection dogs onto the curtilage of a home likewise constitutes a search under the Jones trespass framework

Third-Party Doctrine & Limitations

Individuals generally lack a reasonable expectation of privacy in information, banking records, or phone numbers voluntarily conveyed to third parties^[3].  As established in Hoffa v. United States, 385 U.S. 293 (1966), the fourth amendment does not “protects a wrongdoer’s misplaced belief that a person to whom he voluntarily confides his wrongdoing will not reveal it.” However, historic cell-site location information (CSLI) carries a legitimate expectation of privacy due to its deeply revealing nature, requiring a warrant^[3]

Probable Cause Standard

Probable cause exists when the facts and circumstances within an officer’s knowledge, based on reasonably trustworthy information, are sufficient to warrant a person of reasonable caution to believe that a crime has been committed or that evidence will be found in a specific location[4][5]. It requires a "fair probability," which is more than a mere hunch but less than proof beyond a reasonable doubt

Totality of the Circumstances Test

Courts evaluate probable cause under a flexible totality-of-the-circumstances test, assessing both the quantity and quality of the information collected^[5]. While an informant's "veracity" and "basis of knowledge" remain highly relevant, weakness in one prong may be compensated for by strength in the other or by independent police corroboration

Reasonable Suspicion Standard:

 is a less demanding standard than probable cause, requiring specific, articulable facts that, taken together with rational inferences, suggest criminal activity is afoot

Essential Warrant Requirements: A valid warrant must be:

1. Supported by probable cause^[7];

2. Established under oath or sworn affidavit^[7];

3. Issued by a neutral and detached judicial officer^[7]; and

4. Particularly describing the place to be searched and the persons or items to be seized^[7].

Particularity Requirement:

Warrants must specify the scope of the search to prevent general exploratory searches^[7]. Executing officers may only search areas capable of concealing the items described in the warrant^[7]

Knock-and-Announce Rule:

Officers executing a search warrant must knock, announce their authority and purpose, and allow occupants a reasonable opportunity to respond before making a forced entry, unless reasonable suspicion exists that doing so would endanger officers or lead to evidence destruction^[7]. Violations of the knock-and-announce rule do not trigger the exclusionary rule for seized evidence^[7].

Detaining Occupants During Warrant Execution:

Officers executing a search warrant have limited authority to detain occupants present within the immediate vicinity of the premises while the search is conducted to protect officer safety, prevent flight, and facilitate the search^[7]

Search Incident to Lawful Arrest (SITA): Person & Wingspan:

Upon a lawful custodial arrest, officers may conduct a full warrantless search of the arrestee’s person and the area within their immediate control ("wingspan") for weapons and evidence^[8]

Vehicle SITA ( Gant Rule):

Officers may search the passenger compartment of an arrestee's vehicle incident to arrest only if: (1) the arrestee is unsecured and within reaching distance of the passenger compartment at the time of the search; or (2) it is reasonable to believe the vehicle contains evidence of the offense of arrest^[8].

Breath vs. Blood Tests

Officers may administer a warrantless breath test incident to a drunk-driving arrest, but blood draws generally require a warrant absent specific exigent circumstances^[8].

Exigent Circumstances:

 Officers may enter property without a warrant if probable cause exists alongside urgent necessity, such as rendering emergency aid to an injured occupant, preventing the imminent destruction of evidence, or engaging in hot pursuit of a fleeing felon

Automobile Exception

Officers may conduct a warrantless search of an automobile if they possess probable cause to believe it contains contraband or evidence of crime^[8]. The scope extends to any container inside the vehicle capable of concealing the object of the search, regardless of who owns the container^[8].

Plain View Exception:

Officers may seize items without a warrant if: (1) they are lawfully present in a vantage point; (2) they have lawful physical access to the item; and (3) the incriminating character of the item is immediately apparent^[

voluntary consent searches

Consent eliminates the warrant and probable cause requirements if given voluntarily under the totality of the circumstances, without explicit or implicit police coercion

third party Co-occupant consent search

 A third party with joint access or control over property may provide valid consent^[8]. However, if two co-occupants are physically present and one explicitly objects, the objection overrides the co-occupant's consent as to that present objector

Seizure of a Person Defined

A person is seized under the Fourth Amendment when an officer, by means of physical force or show of authority, intentionally terminates or restrains their freedom of movement such that a reasonable person would believe they are not free to leave

Warrantless Arrest Rules for public arrest

Officers may execute warrantless arrests in public for felonies or misdemeanors committed in their presence if supported by probable cause

Warrantless Arrest Rules home arrest

Absent exigent circumstances or consent, officers cannot make a warrantless entry into a suspect's home to make a routine felony arrest; an arrest warrant is constitutionally required

Terry Stop & Frisk Doctrine:

• Investigatory Stop: An officer may briefly detain an individual for investigative purposes if supported by reasonable suspicion of criminal activity^[6].

• Protective Frisk: An officer may pat down the outer clothing of a lawfully stopped detainee only if the officer possesses independent reasonable suspicion that the suspect is armed and dangerous^[6]. The scope is strictly limited to discovering weapons^[6].

Traffic Stops

• Authority & Scope: Stopping a vehicle requires probable cause of a traffic violation or reasonable suspicion of criminal activity^[6].

• Bright-Line Passenger Orders: Officers may order both the driver and passengers to exit the vehicle during a lawful traffic stop without additional justification^[6].

• Duration Limitation: A traffic stop may not be prolonged beyond the time reasonably required to address the initial traffic infraction (e.g., checking license, registration, warrants) unless independent reasonable suspicion develops. can’t do a dog drug sweep after the stop, has to be during.

Special needs search

A search unsupported by a warrant or individualized suspicion is constitutional under the "special needs" doctrine when non-criminal, non-law-enforcement governmental needs provide sufficient justification.

two prong evaluation test for special needs

1. Impracticality: The government's "special need" renders the warrant and probable cause requirements impracticable^[2].

2. Primary Purpose: The government's primary purpose in searching is distinguishable from the general interest in ordinary crime control^[2].

Administrative warrant

 Search warrants are generally required for administrative housing or municipal code inspections of residential homes and commercial buildings unless a specific exception applies. Warrantless inspections of closely regulated commercial businesses (historically liquor sales, firearms dealing, mining, and automobile junkyards).

the burger test for Pervasively Regulated Industry Exception

1. The inspection is based on a substantial governmental interest informing the regulatory scheme^[4].

2. Warrantless searches are necessary to further the regulatory scheme^[4].

3. The regulatory framework provides a constitutionally adequate substitute for a warrant in terms of the certainty and regularity of its application^[4].

Public School students

Warrantless searches of schoolchildren require only reasonable suspicion rather than probable cause (New Jersey v. T.L.O.)^[4]. Suspicionless drug testing of student athletes and students participating in competitive extracurricular activities is constitutional due to students' reduced privacy expectations, school custodial responsibilities, and the need for swift discipline (Vernonia School District, Earls)^[4][

Safety-Sensitive Adult Employees:

Mandatory drug and alcohol testing of adult public employees without individualized suspicion is valid when tied to safety-sensitive positions, such as railway staff involved in train accidents (Skinner) or customs officers interdicting drugs, carrying firearms, or handling classified documents (Von Raab)^[6].

Political Candidates & Non-Safety Contexts:

State statutes requiring drug testing for political candidates violate the Fourth Amendment absent a demonstrated history of drug abuse by state officials, proof that ordinary law enforcement is inadequate, or safety-sensitive operational hazards (Chandler v. Miller)^[6].

Probationer Home Searches:

A  warrantless search of a probationer's home is constitutional if conducted pursuant to valid probationary regulations supported by reasonable grounds (reasonable suspicion) of a probation violation (Griffin v. Wisconsin)

Parolee Suspicionless Searches:

Suspicionless searches of parolees by law enforcement officers are constitutional because parolees have severely diminished Fourth Amendment privacy expectations stemming from their conditional release status (Samson v. California)^[6].

 Border Search Exception for routine searches

searches of persons, luggage, and vehicles at an international border are reasonable simply because they occur at the border and require no individualized suspicion (United States v. Ramsey)^[6].

 Border Search Exception for non routine searches

Highly intrusive border detentions or searches—including strip searches, body cavity searches, physical destruction of property, or involuntary X-rays—require reasonable suspicion of criminal activity (United States v. Montoya de Hernandez, United States v. Flores-Montano)^[6]

Highway Safety & Sobriety Checkpoints

Sobriety checkpoints are constitutional seizures under a balancing test weighing the gravity of the public safety concern and program effectiveness against the minimal intrusion on individual liberty (Michigan Department of State Police v. Sitz, Brown v. Texas)^[6]

General Crime Control Prohibition:

Vehicle checkpoints whose primary purpose is general crime control or the interdiction of illegal narcotics violate the Fourth Amendment (City of Indianapolis v. Edmond)^[6].

Information-Seeking Checkpoints:

Brief, suspicionless checkpoints established to request public assistance and gather information regarding a specific recent crime committed at that location are constitutional (Illinois v. Lidster)^[6].

Non-Investigative Justifications for inventory searches

Warrantless inventory searches of lawfully impounded vehicles or an arrestee's personal effects are reasonable to protect property from loss or theft, guard police against false claims, and protect officers and the public from danger (South Dakota v. Opperman)^[6].

Standardized Administrative Policy Requirement for inventory searches

 is constitutional only if conducted pursuant to standardized, routine administrative procedures in good faith rather than as a pretext for criminal investigation (Opperman, Florida v. Wells)

Exclusionary Rule

The rule is a judicially created remedy that suppresses unconstitutionally obtained  evidence from the prosecution's case-in-chief when derived from a government violation of the Fourth or Fifth Amendments and deter police misconduct.

Primary v. Secondary Evidence

Primary Evidence is the evidence obtained as an immediate result of an unconstitutional search or seizure. Secondary evidence is known through the Fruit of the Poisonous Tree Doctrine which extends suppression to secondary or derivative evidence that flows from the initial constitutional violation.

Independent Source Exception:

Evidence is admissible if it was discovered by means wholly independent of any constitutional violation, placing law enforcement in the same position as if no error had occurred. 

Inevitable Discovery Exception

Illegally obtained evidence is admissible if the government demonstrates that the evidence inevitably would have been discovered through independent, lawful investigative means. 

Attenuation Doctrine

Derivative evidence is admissible if the causal connection between the official misconduct and the evidence's discovery is sufficiently remote, weak, or attenuated

what three factors do Courts evaluate when using attenuation

1. Temporal Proximity: The time elapsed between the initial constitutional violation and the discovery of evidence (longer periods favor attenuation)^[2].

2. Intervening Circumstances: The presence of independent intervening events (e.g., a defendant's voluntary act or the discovery of a valid, pre-existing arrest warrant)^[2].

3. Purpose and Flagrancy of Misconduct: Whether the police violation was deliberate/flagrant or merely a good-faith oversight

under the good faith exception when evidence seized in violation of the Fourth Amendment is admissible if law enforcement officers acted with objective good faith and reasonable reliance on

• A search warrant issued by a neutral magistrate, even if later found to lack probable cause^[2];

• Computerized police or court records containing clerical errors regarding outstanding warrants^[2];

• Binding judicial precedent existing at the time of the search^[2]; or

• An officer's objectively reasonable mistake of law^[2].

what is the limitation on the good faith doctrine

The exception does not apply to deliberate, reckless, or grossly negligent police conduct, or systemic governmental negligence

Non-Criminal & Collateral Proceedings:

The exclusionary rule generally applies only to the trial phase of a criminal prosecution. It does not bar the use of illegally seized evidence in grand jury proceedings, civil tax cases, civil deportation proceedings, parole revocation hearings, or judicial sentencing decisions^[2].

Defendant Impeachment Exception:

Evidence or statements suppressed under the Fourth Amendment may be introduced at trial for the limited purpose of impeaching a testifying defendant's testimony given on direct examination or cross-examination reasonably suggested by direct testimony^[2].