The Fourth Amendment is the most powerful defense tool in many criminal cases. If police searched you, your car, or your home without legal justification, the evidence they found may be suppressible. Here's the framework for evaluating your search and building the challenge.
The Fourth Amendment's default rule is simple: searches and seizures must be based on a warrant supported by probable cause. Everything else — every warrantless search, every stop, every pat-down — is an exception to that default. The government bears the burden of proving that an exception applies.
That burden allocation matters. When you challenge a search, you don't have to prove it was unlawful. The prosecution must prove it was lawful. Your job is to identify which exception they're relying on, then undermine the factual basis for that exception.
Begin by asking: was there a warrant? If yes, you challenge the warrant. If no, you identify which exception the prosecution claims applied — and then challenge whether the facts actually support that exception. Once you have your challenge identified, the suppression motion is where you bring it to court.
If a warrant was obtained, read it carefully along with the supporting affidavit. Warrants can be challenged on several grounds:
The affidavit must establish probable cause — a fair probability that the items sought will be found in the place to be searched. Conclusory statements ("I believe drugs are present") without supporting facts are insufficient. Stale information — tips or observations from weeks or months earlier — may not establish present probable cause. Analyze whether the affidavit's specific facts, taken together, actually support the inference the officer drew.
Under Franks v. Delaware (1978), you can challenge the veracity of the warrant affidavit itself. If you can make a "substantial preliminary showing" that the affiant deliberately or recklessly included false statements, and that those false statements were necessary to the finding of probable cause, the warrant must be voided and the evidence suppressed. This requires specific, documented evidence of the false statements — not a general allegation that the officer lied.
The Fourth Amendment requires warrants to "particularly describe the place to be searched, and the persons or things to be seized." A warrant that authorizes a search of an entire property when probable cause exists only for a specific area, or that authorizes seizure of vaguely described items, may be constitutionally defective. Look for broad catchall language like "any and all documents" or "any items of evidentiary value."
Even a valid warrant doesn't authorize unlimited searching. Police must search only in places where the items sought could reasonably be found. A warrant to search for a stolen television doesn't authorize searching through a small box. Items seized outside the warrant's authorized scope may be suppressed even when the warrant itself was valid.
If there was no warrant, the prosecution must justify the search under one of these recognized exceptions. Here is how to analyze each one:
Terry v. Ohio (1968) allows officers to briefly detain and pat down a person for weapons if they have reasonable articulable suspicion of criminal activity. Reasonable suspicion is less than probable cause but more than a hunch — the officer must point to specific, articulable facts.
Officers may search the person and the area within their immediate control at the time of a lawful arrest. The search must be contemporaneous with a valid arrest. Riley v. California (2014) specifically held that cell phones require a warrant — they are not subject to search incident to arrest.
If officers have probable cause to believe a vehicle contains contraband or evidence of a crime, they may search the vehicle without a warrant — including all areas where the items could reasonably be found. The justification is the vehicle's inherent mobility. The automobile exception does not require exigent circumstances.
Officers can seize items in plain view if they are lawfully present in the location and the incriminating nature of the item is immediately apparent. Three requirements: the officer must be lawfully present, the item must be in plain view, and its incriminating character must be immediately apparent without any further manipulation.
A voluntary consent to search waives the warrant requirement. Consent must be freely and voluntarily given — not coerced, not implied by the authority of the officer's presence. You do not need to be told you have the right to refuse, though the absence of that advisement is relevant to whether consent was truly voluntary.
True emergencies — hot pursuit of a fleeing suspect, imminent destruction of evidence, emergency aid — can justify warrantless entry. The circumstances must be genuine and not manufactured by the police themselves.
Work through this sequence with your police report and discovery documents in hand:
The stop, the pat-down, the search of the vehicle, the search of the home, the seizure of the phone — each is a separate Fourth Amendment event. List them individually. Each requires its own legal justification.
Read the police report carefully. What specific facts does the officer claim gave them the right to stop you, search you, or enter the property? Write them down verbatim — these are the facts you need to challenge.
For a Terry stop, do the specific facts add up to reasonable suspicion? For probable cause, do the facts establish a fair probability? For consent, was it actually voluntary? Apply the legal standard to the facts — not in the abstract, but with the specific circumstances of your case.
If the initial stop was unlawful, everything that flowed from it may be suppressible — the subsequent search, anything found in that search, and any statements made during or after the unlawful detention. Map the chain from the unlawful act to each piece of evidence you want excluded.
Use Brief to do this analysis on your specific facts. Upload your police report and discovery to Brief. Brief reads the specific facts of your stop and search against the applicable Fourth Amendment standards, identifies which exception the prosecution is likely to rely on, and shows you where the legal analysis is strongest and weakest in your specific case — before you write the motion.
Upload your police report. Brief identifies what the officer claims justified the search, tests those facts against the applicable legal standard, and tells you which Fourth Amendment arguments are strongest in your case — so you file a motion built on real analysis, not guesswork.
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Once you've identified your Fourth Amendment argument, here's how to write the motion and present it at the hearing.
At the suppression hearing, you get to cross-examine the officer about the search. Here's how to do it effectively.
Upload your police report. Brief applies the Fourth Amendment framework to your specific facts and identifies your strongest suppression arguments.