Search and seizure is a legal procedure in which law enforcement officials conduct an examination of a person’s property or premises to look for evidence of a crime and take possession of any relevant items found.
As part of the Bill of Rights, American citizens are protected from unreasonable searches and unlawful seizures. While this portion is straightforward, the laws surrounding search and seizure can be complex, and many assumptions are not accurate. When law enforcement misuses these processes, it can be enough to have a case thrown out or significant evidence deemed inadmissible. In any case where a search or seizure becomes relevant, it is critical to have a skilled federal criminal defense attorney on your team to help you determine if all laws and guidelines were followed.
The Fourth Amendment
Protections regarding search and seizure are laid out in the Fourth Amendment to the United States Constitution. The text of this Amendment reads: “The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable search 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 person or things to be seized.”
In this context, search can apply to any property that is evaluated, while seizure refers to the taking of something into custody. This can be evidence that is collected or a person who is arrested.
These provisions were included in the Amendment to protect privacy by protecting against unreasonable search and seizure by state and federal law enforcement authorities. At the same time, the Fourth Amendment permits reasonable searches and seizures. This gives police the ability to override privacy concerns and conduct searches of you, your home, and other property, your paperwork, your trash, or anything else. This can only happen if the police have probable cause to believe they will find evidence that you committed a crime, and a judge issues a warrant, or if the particular circumstances justify a search without a warrant first.
What Is Probable Cause?
Probable cause is established when law enforcement can point to objective circumstances that lead them to suspect someone committed a crime. They then present this evidence to a judge who determines whether or not probable cause exists.
Whether probable cause is present is determined on a case-by-case basis, usually before a warrant is issued, though in some cases, it may be determined after the fact.
Does The Fourth Amendment Always Apply?
The Fourth Amendment applies only to searches wherein the person has a “legitimate expectation of privacy” regarding the place or item searched. When this is not true, there is no protection. This is usually determined by a two-part test that determines where this legitimate expectation exists:
- Did the person actually expect privacy?
- Is the person’s expectation objectively reasonable in society?
For example, when you use a public restroom, you have the right not to be spied on. This is generally considered reasonable, and something like a hidden video camera would violate your privacy in this case. Even if you performed an illegal activity in the restroom, your right to privacy would protect you from a search that used that tape. However, if you are pulled over by a police officer who notices a weapon or drug paraphernalia on the passenger seat, the open nature of your vehicle would not grant privacy.
Who Can Carry Out Search and Seizure?

In the United States, there have been times when private security personnel outnumbered police officers by three-to-one. You may see these personnel working in offices or residential buildings, in stores, or even patrolling a neighborhood. It is not always obvious whether they are a police officer or private personnel. However, the Fourth Amendment does not apply to searches carried out by non-governmental employees who are not acting on behalf of the government.
For example, imagine a mall security guard who sees a teenager and concludes, with no objective evidence, that they have shoplifted. The guard could detain the teenager and open their backpack, where they find stolen goods or illegal drugs. They can then call the police, and the item would be admissible in court because they acted on their own and not at the behest of the government.
Consequences of Unreasonable Search and Seizure

If it becomes apparent that a search performed by an officer was illegal, it can have several effects on a case. Several rules exist for these scenarios.
The Exclusionary Rule
If a court reviews evidence and finds that an unreasonable search occurred, any evidence seized during that search cannot be used as direct evidence in a criminal prosecution. This rule was established by the Supreme Court of the United States in 1961 and has been controversial. The goal is to dissuade police from conducting illegal searches and ensure the proper steps are taken. There are exceptions to this rule for “good faith” searches.
Fruit of the Poisonous Tree Doctrine
In addition to any seized evidence being inadmissible, any evidence derived from the initial evidence can also not be used. For example, if someone is suspected of selling phony gift cards, a police officer may unlawfully enter their home and seize a map of the location of the gift cards. Using the map, the officer may then find the cards themselves. Because the map was obtained illegally, the map and the gift cards are both inadmissible in court.
There is a common belief that if a defendant can show a search was illegal, the case will be dismissed, which is not accurate in all cases. If a prosecutor has enough admissible evidence, the case can continue, and a defendant may still be found guilty. Judges can also consider illegally seized evidence when they determine a sentence following a conviction. Civil cases and deportation cases can also use this evidence. In some cases, a prosecutor may even be able to use the evidence to attack the credibility of a defendant who testifies at trial.
An experienced defense attorney will be able to examine the evidence and determine what may or may not be admissible by the rules of search and seizure, and apply these laws to your case.
FAQS on Search and Seizures Under U.S. Law
What happens if police search my house without a warrant?
Generally, warrantless searches are unconstitutional under the Fourth Amendment unless exceptions apply. If police searched without a warrant and no exception exists, any evidence found may be suppressed through the exclusionary rule, meaning it cannot be used against you in court. Common exceptions include consent, exigent circumstances, plain view, search incident to arrest, and automobile exceptions.
Can I refuse to let the police search my car during a traffic stop?
Yes, you have the right to refuse consent to a search. However, police can still search without your consent if they have probable cause to believe the vehicle contains evidence of a crime or contraband. They can also search the passenger compartment if they arrest an occupant and it’s reasonable to believe evidence related to the arrest might be found there.
Do police need a warrant to look through my phone?
Yes. The Supreme Court ruled in Riley v. California that police generally need a warrant to search your cell phone, even after a lawful arrest. Digital information on phones receives strong Fourth Amendment protection due to the vast amount of personal data stored on modern devices.
What should I do if the police knock on my door and ask to come inside?
You are not required to let them in unless they have a warrant. You can step outside and close the door behind you to speak with them, or speak through a closed door. Politely ask if they have a warrant. If they do, ask to see it and verify it’s properly signed and describes your address. If they don’t have a warrant, you can decline their entry.
Can police search my home if they smell marijuana?
The answer varies by jurisdiction. In states where marijuana remains illegal, the smell of marijuana can provide probable cause for a search. However, in states where marijuana is legal for recreational or medical use, courts have increasingly held that the smell alone is insufficient to establish probable cause, as the odor could be from legal marijuana.
What are exigent circumstances that allow warrantless searches?
Exigent circumstances are emergencies requiring immediate action. These include hot pursuit of a fleeing suspect, preventing imminent destruction of evidence, responding to screams or sounds of violence, preventing a suspect’s escape, and addressing threats to officer or public safety. The emergency must be genuine and not manufactured by the police.
Can police search my property if I’m on probation or parole?
Yes, usually. Probation and parole conditions typically include reduced Fourth Amendment protections. Many supervision agreements include search clauses allowing officers to search you, your residence, and your vehicle without a warrant or probable cause. Courts have upheld these conditions as reasonable, given the rehabilitative and supervisory nature of probation and parole.
What is the plain view doctrine?
The plain view doctrine allows police to seize evidence without a warrant if they are lawfully in a location, the item is in plain view, and its incriminating nature is immediately apparent. For example, if police are legally in your home with a warrant for one item and see illegal drugs on your coffee table, they can seize the drugs.
Can police use thermal imaging or drones to search my property?
Thermal imaging devices that detect heat patterns inside a home generally require a warrant, as established in Kyllo v. United States. For drones, the law is still developing. Police generally need a warrant to use drones for targeted surveillance of private property where you have a reasonable expectation of privacy, though regulations vary by state.
What is a knock-and-announce requirement?
Police executing a search warrant must typically knock, announce their presence and purpose, and wait a reasonable time for occupants to open the door before forcing entry. This requirement protects privacy, prevents violence, and allows time for verification. However, courts may issue no-knock warrants if announcing would create danger or allow evidence destruction.
Can police search my backyard without permission?
It depends on the area. The curtilage, the area immediately surrounding your home, receives Fourth Amendment protection and generally requires a warrant to search. Open fields farther from your home receive less protection under the open fields doctrine. Fenced yards close to your home typically require a warrant, while distant portions of large properties may not.
What should I do if I think the police violated my Fourth Amendment rights?
Document everything you remember about the search, including dates, times, locations, officers’ names and badge numbers, what was said, and what was seized. Do not resist physically. Tell your attorney immediately. Your lawyer can file a motion to suppress evidence, challenging the legality of the search. Illegal searches can result in evidence being excluded from your trial.
Can police search my trash?
Yes. The Supreme Court ruled in California v. Greenwood that trash left for collection in public areas has no reasonable expectation of privacy. Once you place garbage on the curb for pickup, police can search it without a warrant. However, trash within your home or property curtilage retains Fourth Amendment protection.
What is reasonable suspicion versus probable cause?
Reasonable suspicion is a lower standard requiring specific, articulable facts suggesting criminal activity may be occurring. It allows brief investigative stops and pat-downs for weapons. Probable cause is a higher standard requiring facts and circumstances that would lead a reasonable person to believe a crime has been, is being, or will be committed. It’s required for arrests and most searches.
Can police search my car after giving me a speeding ticket?
Not automatically. A traffic citation alone doesn’t authorize a search. However, police can search if they have probable cause to believe your vehicle contains evidence of a crime, if they arrest you and search incident to that arrest, if you consent, or if they conduct an inventory search after impounding your vehicle according to standard procedures.
Do I have to answer questions during a search?
No. You have Fifth Amendment rights against self-incrimination and can remain silent. You should clearly state you wish to remain silent and want an attorney. You must provide identification when legally required to do so, but you don’t have to answer questions about where you’ve been, what you’re doing, or consent to searches.
Can police search shared spaces in apartments or houses with roommates?
Any person with authority over shared common areas can generally consent to a search of those areas. However, a roommate cannot consent to a search of your private bedroom or areas under your exclusive control. If you share a bedroom, the consent rules become more complex and depend on whether you had a reasonable expectation of privacy in specific areas.
What is an inventory search?
An inventory search occurs when police impound a vehicle or arrest someone and catalogue their belongings. These searches don’t require probable cause or a warrant but must follow standardized procedures established by the police department. Their purpose is to protect the owner’s property and protect the police from liability, not to investigate crimes, though evidence discovered can be used against you.
Can police extend a traffic stop to bring drug dogs?
Police cannot extend a traffic stop beyond the time needed to complete the stop’s original purpose solely to wait for a drug dog, according to Rodriguez v. United States. However, if the dog arrives while police are still addressing the traffic violation, registration, insurance, and warrant checks, the dog sniff is permissible as long as it doesn’t prolong the stop.
What happens if police find evidence while executing a warrant for something else?
If police are lawfully executing a valid warrant and find evidence of other crimes in plain view or while searching areas covered by the warrant, they can seize that evidence. For example, if police have a warrant to search for stolen electronics and find illegal drugs while looking in places where electronics could be hidden, the drugs can be seized and used as evidence.