Case Law

Terry v. Ohio

• Police may briefly detain someone with reasonable suspicion that criminal activity is occurring.

• A frisk/pat-down is allowed when the officer reasonably believes the person is armed and dangerous.

• Reasonable suspicion ≠ probable cause.

• Stop must be justified at inception and limited in scope/duration to the circumstances.
  This landmark Supreme Court case established the "stop and frisk" principle, allowing law enforcement to stop a person based on reasonable suspicion without a warrant.

Muehler v. Mena

• Officers executing a valid search warrant may detain occupants while the search is conducted.

• Handcuffs can be reasonable when justified by officer/occupant safety concerns.

• In this case, officers could also ask ____ about her immigration status without separate reasonable suspicion, because the questioning did not unlawfully prolong the detention.

This case established that law enforcement can detain individuals during the execution of a search warrant and ask questions about immigration status without creating additional legal issues.

People v. Matelski

• Officers went to a probationer's home who had a search condition.

• Two people leaving the home were briefly detained.

• Officers obtained their identifying information and discovered outstanding warrants.

• Court upheld the detention because it was brief/minimal and officers had legitimate reasons to determine their connection to the probationer and address safety concerns
  
  This case affirmed that law enforcement can briefly detain individuals at a probationer's residence if there are safety concerns and reasonable suspicion of their connection to the probationer.

Maryland v. Buie

• Areas immediately adjoining the arrest location may generally be checked as a safety precaution.

• For broader areas, officers need reasonable suspicion based on specific, articulable facts that a dangerous person may be present.

• It is NOT a full search for evidence.

• Sweep must be limited in scope and duration.
  This case established that law enforcement may perform a limited protective sweep of the area immediately surrounding an arrest to ensure officer safety, without constituting a full search for evidence.

People v. Rios

• Officers went to a residence to conduct a probation search.

• ____ was present as a temporary visitor.

• Officers detained ____and conducted a pat search.

• The court held the detention was reasonable under the circumstances.

• ____had no legitimate expectation of privacy in the residence because he was only a temporary visitor.

• The pat search was permissible because officers had reason to believe he could be armed and dangerous.

• A firearm was discovered
  
  

Graham v. Connor

• was stopped by police after an officer suspected suspicious activity.

• Officers detained _______ and used physical force during the encounter.

• claimed the officers used excessive force.

• The court established that police use of force is judged under the Fourth Amendment's objective reasonableness standard.

• The reasonableness of the force is determined by the facts and circumstances facing the officer at the time.

• Important factors include the severity of the suspected crime, immediate threat, and resistance or flight.

• The officer's personal intent or motivation is not the controlling factor.

The analysis considers the totality of the circumstances from the perspective of a reasonable officer on the scene.

People v. Carreon

• _____ was not on probation but was living in a separate converted garage on the probationer's property.

• Officers conducted a probation search of the residence.

• Officers searched _____ living area, drawers, and purse, finding methamphetamine.

• _____ challenged the search, arguing that it violated her Fourth Amendment rights.

• The court established that a probation search condition does not automatically authorize searches of property belonging to a non-probationer.

• Officers must have a reasonable basis to believe the probationer has authority or control over the area or property being searched.

• A non-probationer's personal belongings, such as a purse, may retain Fourth Amendment protection.

• Physical access to an area or container does not by itself establish legal authority to search it.

• The scope of a probation search is determined by the circumstances known to the officers at the time of the search.
  
  

Beaver v City of Federal Way

• _____ was arrested for residential burglary after attempting to flee from police and failing to comply with officers' commands.

• Officers used a Taser on _____ five times during the arrest.

• _____ claimed the repeated Taser deployments constituted excessive force under the Fourth Amendment.

• The court established that each Taser application constitutes an additional use of force and must be justified by the circumstances at that point in the encounter.

• Multiple Taser applications cannot be justified solely because a suspect fails to comply with commands, absent other indications that the suspect is about to flee or poses an immediate threat to an officer.

• Officers must consider whether the suspect is capable of complying with the officer's commands before applying additional force.

• The court found the first three Taser applications were not excessive, but the fourth and fifth applications violated _____ Fourth Amendment rights because the circumstances had changed and he was no longer presenting the same immediate threat.

• However, the officers were ultimately protected by qualified immunity because the law was not clearly established at the time that their conduct was unconstitutional.

City and County of San Francisco v Sheehan

• _____ was a mentally ill woman living in a group home who became agitated and threatened her social worker.

• Officers responded to take _____ to a mental health facility for evaluation.

• When officers entered her room, _____ grabbed a knife and threatened to kill them.

• Officers initially retreated and closed the door, but then reentered the room.

• _____ again confronted the officers with the knife. Officers used pepper spray and then shot her multiple times.

• _____ claimed the officers violated her Fourth Amendment rights and that they should have accommodated her mental illness.

• The Supreme Court held that the officers' use of force was reasonable under the circumstances, given that Sheehan was armed and threatening the officers.

• The Court also held that the officers were entitled to qualified immunity because there was no clearly established Fourth Amendment right requiring them to accommodate _____ mental illness in the specific circumstances.

• The Supreme Court did not decide whether the Fourth Amendment actually requires officers to accommodate a person's mental illness in circumstances like these, because the alleged right was not clearly established at the time.

• The Court also did not decide the ADA question presented in the case because that issue was dismissed as improvidently granted.

Estate of Ronald Armstrong v. The Village of Pinehurst

• _____ was a mentally ill man who was subject to an involuntary commitment order requiring him to be taken to a hospital.

• Officers located _____ outside the hospital and attempted to take him into custody.

• _____ sat on the ground and wrapped himself around a post, refusing to let go.

• Officers attempted to physically remove him but were unsuccessful.

• An officer warned _____ that he would be tased if he did not let go of the post.

• _____ continued to hold onto the post, and the officer deployed a Taser multiple times.

• _____ estate claimed the officers used excessive force in violation of the Fourth Amendment.

• The Fourth Circuit held that the officers' use of the Taser was unconstitutionally excessive under the circumstances.

• The court emphasized that physical resistance is not automatically the same as an immediate threat to officer safety.

• Taser use must be proportional to the circumstances and should be based on an objectively reasonable belief that there is an immediate safety risk that the Taser is likely to address.

• The court noted that _____ was stationary, unarmed, surrounded by officers, and resisting nonviolently.

• The fact that _____ was not complying with the officers' commands did not, by itself, justify the use of a Taser.

• The officers nevertheless received qualified immunity because, at the time of the incident, the specific constitutional rule was not clearly established.

Bryan v. MacPherson

Incident: Carl Bryan was stopped by police for a seatbelt violation.

Behavior: Bryan was upset, yelling, and acting erratically but was unarmed.

Officer's Action: Officer MacPherson deployed his Taser without warning.

Injuries: Bryan fell face-first onto the pavement, breaking four teeth and suffering facial injuries.

Legal Issue: Whether the Taser use violated the Fourth Amendment's protection against excessive force.

Court Ruling: The court found the Taser use objectively unreasonable because Bryan posed no immediate threat.

Key Principle: Officers must have a reasonable justification for using significant force.

Qualified Immunity: A revised 2010 decision granted the officer qualified immunity because the law was not clearly established at the time.

Singh v. City of Phoenix

Incident: Phoenix police responded to a reported attempted robbery involving a knife in 2019.

Behavior: Krish Singh was holding a knife to his own neck and asking officers to shoot him.

Officer's Action: Officer Brittany Smith-Petersen shot Singh after he refused commands to drop the knife.

Injuries: Singh was seriously injured by the gunshot.

Legal Issue: Whether the officer's use of deadly force violated the Fourth Amendment's protection against excessive force.

Court Ruling: The Ninth Circuit ruled that the officer was not entitled to qualified immunity at this stage, allowing the excessive-force lawsuit to proceed.

Key Principle: Possessing a weapon does not automatically justify deadly force when the individual poses no immediate threat to officers or others.

Qualified Immunity: The court found that previous case law had clearly established relevant limits on deadly force

Case v Montana

Incident: Police responded to William Case's home after his ex-girlfriend reported he was threatening suicide.

Behavior: Case did not respond to officers knocking or calling out. Officers saw an empty gun holster and what appeared to be a suicide note.

Officer's Action: Officers entered the home without a warrant to provide emergency assistance.

Use of Force: Case emerged from a closet holding what appeared to be a gun. An officer shot and injured him.

Legal Issue: Whether police can enter a home without a warrant to provide emergency aid without probable cause.

Court Ruling: On January 14, 2026, the U.S. Supreme Court unanimously ruled 9–0 that the warrantless entry was constitutional.

Key Principle: Officers may enter a home without a warrant when they have an objectively reasonable basis to believe someone inside is seriously injured or in imminent danger.

Fourth Amendment: Probable cause is not required for the emergency-aid exception, but officers must have an objectively reasonable justification

US v Patterson

Incident: Probation officers searched Kenneth Miller's apartment because Miller was on parole.

Officer's Action: Officers searched a separate bedroom belonging to Kirk Patterson.

Evidence Found: Officers discovered a handgun, ammunition, and ecstasy.

Probation Verification: Officers discovered Patterson's probation paperwork during the search. Their testimony conflicted about when they confirmed his search waiver.

Legal Issue: Could officers justify the search using Patterson's probation status if they had not verified his search waiver beforehand?

Court Ruling: The court ruled the search unlawful and granted Patterson's motion to suppress evidence.

Fourth Amendment: Officers cannot retroactively justify a search based on a probation search waiver discovered afterward.

Key Principle: Officers must know about a valid probation search condition before relying on it to justify a warrantless search.

United States v. Cervantes (2017)

Incident: Officers contacted Cervantes, who was under mandatory supervision, and discovered he was staying in a hotel room.

Officer's Action: Officers conducted a warrantless search of Cervantes' hotel room based on his mandatory supervision search conditions.

Evidence Found: Officers discovered evidence of criminal activity during the search.

Supervision Verification: Officers confirmed Cervantes was subject to mandatory supervision, which included a search condition.

Legal Issue: Could officers conduct a warrantless search without reasonable suspicion based on Cervantes' mandatory supervision conditions?

Court Ruling: The Ninth Circuit ruled the search lawful because Cervantes had a reduced expectation of privacy under his supervision conditions.

Fourth Amendment: Individuals under valid mandatory supervision search conditions may be subject to warrantless, suspicionless searches.

Key Principle: Officers may conduct a warrantless search based on valid supervision conditions when they have lawful authority and comply with the conditions.

Young v. County of Los Angeles (2011)

Incident: Young was stopped by a deputy for a seatbelt violation. During the encounter, Young exited his vehicle and sat on the curb.

Officer's Action: The deputy ordered Young to return to his vehicle. When Young refused, the deputy used pepper spray and struck him with a baton.

Force Used: The deputy used intermediate force, including pepper spray and baton strikes, against Young.

Suspect's Behavior: Young was initially noncompliant with verbal commands but was not presenting an immediate physical threat.

Legal Issue: Was the deputy's use of pepper spray and baton strikes objectively reasonable under the circumstances?

Court Ruling: The Ninth Circuit determined that the use of significant force against a person suspected of minor violations who posed no immediate threat could violate the Fourth Amendment.

Fourth Amendment: Officers must use objectively reasonable force based on the severity of the offense, immediate threat, and level of resistance.

Key Principle: Verbal noncompliance alone does not automatically justify intermediate force when the individual poses no immediate threat.

United States v. Barry (2025)

Incident: Officers investigated information that Ryan Barry, who was under post-release community supervision, was involved in drug activity at an apartment.

Officer's Action: Officers conducted a warrantless search of the apartment based on Barry's supervision search conditions.

Evidence Found: Officers discovered evidence of criminal activity during the apartment search.

Residency Verification: Officers relied on Barry's statements, possession of a key, and other information connecting him to the apartment.

Legal Issue: Did officers have probable cause to believe Barry lived at the apartment before conducting a warrantless supervision search?

Court Ruling: The Ninth Circuit upheld the search because officers had probable cause to believe Barry resided at the apartment.

Fourth Amendment: Officers must establish probable cause that a supervised individual resides at a location before searching that residence under the applicable supervision search exception.

Key Principle: Officers must have probable cause to believe a supervised individual lives at the residence before relying on that person's search conditions to search it.

Bradley v. Benton (2021)

Incident: During a traffic stop, a passenger named Robinson fled from officers and climbed onto an approximately eight-foot wall.

Officer's Action: An officer pursued Robinson and allegedly deployed a Taser while Robinson was on top of the wall.

Force Used: The officer used a Taser, which is generally considered a less-lethal weapon.

Result: Robinson fell from the wall, suffered a broken neck, and died.

Legal Issue: Could deploying a Taser against someone standing on an elevated surface constitute excessive deadly force?

Court Ruling: The Eleventh Circuit determined that, under the plaintiffs' version of events, the Taser use constituted unreasonable deadly force and allowed the excessive-force claim to proceed.

Fourth Amendment: A less-lethal weapon can constitute deadly force when its use creates a substantial risk of death or serious bodily injury.

Key Principle: Officers must evaluate the environment and potential consequences before deploying a Taser because less-lethal force can become deadly force depending on the circumstances.

Illinois v. Wardlow (2000)

Incident: Sam Wardlow was standing near a building in a Chicago neighborhood known for heavy narcotics trafficking when he noticed police officers approaching and immediately ran.

Officer's Action: Officers pursued Wardlow, stopped him, and conducted a protective pat-down search.

Evidence Found: Officers discovered a loaded .38-caliber handgun inside a bag Wardlow was carrying.

Probation Verification: Not applicable. Wardlow's detention was based on his flight and surrounding circumstances, not probation or parole status.

Legal Issue: Did Wardlow's unprovoked flight upon seeing police in a high-crime area establish reasonable suspicion to justify an investigative detention?

Court Ruling: The United States Supreme Court ruled that officers had reasonable suspicion to stop Wardlow under the Fourth Amendment.

Fourth Amendment: Unprovoked flight in an area known for criminal activity can establish reasonable suspicion when considered under the totality of the circumstances.

Key Principle: Officers may conduct an investigative detention when specific, articulable facts support reasonable suspicion. Presence in a high-crime area alone is insufficient, but unprovoked flight is a significant additional factor.

United States v. Grandberry (9th Cir. 2013)

Incident: Police investigated suspected drug trafficking involving Lambert Grandberry, a parolee. Officers observed Grandberry entering an apartment multiple times but lacked sufficient evidence that he actually lived there.

Officer's Action: Officers arrested Grandberry and conducted a warrantless search of the apartment, relying on his parole search condition.

Evidence Found: Officers discovered a firearm and approximately 75 grams of crack cocaine inside the apartment.

Probation Verification: Officers knew Grandberry was on parole and subject to a search condition. However, they did not establish probable cause that the apartment was his residence.

Legal Issue: Could officers search an apartment without a warrant under Grandberry's parole search condition when they lacked probable cause to believe he lived there?

Court Ruling: The Ninth Circuit affirmed the suppression of evidence because officers lacked probable cause to believe Grandberry resided at the searched apartment.

Fourth Amendment: A parole search condition does not automatically authorize officers to search any residence a parolee visits or potentially controls.

Key Principle: Before conducting a warrantless residential search based on a parole condition, officers must have probable cause to believe the parolee actually resides at that location. Merely visiting or entering a residence is insufficient.

People v. Valencia (2026)

Incident: Isaias Valencia fled from police during a dangerous high-speed vehicle pursuit. After crashing, Valencia ran into his apartment and barricaded himself inside a bedroom, leading to an overnight standoff.

Officer's Action: Officers entered Valencia's apartment without a warrant while pursuing him for felony evasion. During the standoff, police maintained their response and ultimately used force to enter the barricaded bedroom.

Evidence Found: Evidence included firearms-related evidence, evidence of the shootings of responding officers, and toxicology results confirming methamphetamine and cocaine use.

Probation Verification: Not applicable. The warrantless entry was justified under exigent circumstances, not probation or parole search conditions.

Legal Issue: Could officers lawfully enter Valencia's apartment without a warrant during hot pursuit of a fleeing felon, and were they required to obtain a warrant as the standoff continued?

Court Ruling: The California Court of Appeal held that jurors could find exigent circumstances justified the initial warrantless entry. Officers were not required to interrupt their ongoing response to obtain a warrant during the standoff. The judgment was otherwise affirmed, with a remand to correct sentencing errors.

Fourth Amendment: Warrantless entry into a home may be justified by exigent circumstances, including immediate pursuit, serious safety threats, and the potential loss of evidence, depending on the totality of circumstances.

Key Principle: Officers may enter a residence without a warrant when objectively reasonable exigent circumstances require immediate action. A continuing emergency does not necessarily require officers to suspend their response to obtain a warrant.

County of Nevada v. Superior Court (2025)

Incident: Nevada County sheriff's deputies responded to a welfare check involving a mother, Crawford, and her two young children. Crawford was behaving erratically and carrying a knife. During the encounter, she advanced toward deputies with the weapon.

Officer's Action: Deputy Matthew Harrison deployed his Taser when Crawford advanced toward him with the knife. The Taser did not stop her, and Deputy Caleb Toderean fired his service weapon, fatally shooting Crawford.

Evidence Found: The incident involved a knife, deputy testimony, and evidence concerning the sequence of events and the officers' use of force. The case concerned civil liability rather than suppression of physical evidence.

Probation Verification: Not applicable. The case involved police use of force during a welfare check, not probation or parole searches.

Legal Issue: Did Deputy Harrison act unreasonably by approaching Crawford and deploying his Taser, potentially creating liability for excessive force, negligence, and civil rights violations?

Court Ruling: The California Court of Appeal ruled that Deputy Harrison's actions were objectively reasonable under the circumstances. It directed the trial court to grant summary judgment in favor of Harrison and the County.

Fourth Amendment: Police use of force must be evaluated objectively from the perspective of a reasonable officer at the scene, considering the totality of the circumstances rather than hindsight.

Key Principle: Officers are not constitutionally required to choose the least intrusive or most reasonable possible tactic. Their actions must fall within the range of objectively reasonable responses to the circumstances confronting them, including immediate threats and rapidly evolving dangers.