Police generally cannot conduct a warrantless cell phone search of the digital contents of a phone they seize during an arrest. Since the U.S. Supreme Court’s 2014 decision in Riley v. California, officers need a warrant supported by probable cause before browsing through photos, messages, call logs, or other data stored on a phone taken from an arrestee. A few narrow exceptions still exist, and how you respond after the fact matters as much as the constitutional rule itself.
The General Rule After Riley v. California
In June 2014, the Supreme Court held that police generally may not search the digital information on a cell phone seized from someone they’ve arrested without first obtaining a warrant.1Justia U.S. Supreme Court Center. Riley v. California, 573 U.S. 373 (2014) Before Riley, many courts treated a phone found on an arrestee like any other physical container, similar to a wallet or cigarette pack, whose contents an officer could inspect under the “search incident to arrest” doctrine. That doctrine is a longstanding exception to the Fourth Amendment’s warrant requirement, and it allows officers who make a lawful arrest to search the person and their immediate belongings to protect officer safety and prevent evidence from being destroyed.2Legal Information Institute. Search Incident to Arrest Doctrine
Riley rejected that analogy for phones. The Court recognized that a cell phone is fundamentally different from a wallet or address book. The sheer volume and variety of personal data stored on a phone creates privacy interests that far outweigh the usual justifications for warrantless searches. Neither officer safety nor evidence preservation, the two rationales behind searches incident to arrest, applies meaningfully to digital data on a phone already in police custody. The old rule that let officers freely browse through a phone’s contents simply because it was found during an arrest was gone.
The Narrow Exceptions That Remain
Riley did not ban every warrantless look at a phone. Two carveouts continue to matter in practice.
Exigent Circumstances
The Court preserved the exigent circumstances exception, where police face a genuine emergency such as an imminent threat to someone’s life. In those situations, officers may act without a warrant, though the emergency must be real and specific rather than a general suspicion that evidence exists.
Plain View
The plain view doctrine also survives Riley, and Maryland’s highest court showed how it can apply to a phone in Sinclair v. State. In that case, an officer physically opened a flip phone seized during a lawful arrest. The screen saver displayed an image of custom wheel rims that matched those on a stolen car. The Maryland Court of Appeals held the image was admissible under plain view, which requires three conditions: the officer’s initial intrusion was lawful, the incriminating nature of the evidence was immediately apparent, and the officer had a lawful right of access to the item.3Justia. Sinclair v. State – Court of Appeals of Maryland
The court reasoned that Riley itself allows an officer who seizes a flip phone during a lawful arrest to physically inspect and secure it, including opening it to check for hidden weapons, powering it off, or removing the battery. Because the screen saver appeared automatically when the phone was opened, the officer saw it without conducting any search of the phone’s digital contents.3Justia. Sinclair v. State – Court of Appeals of Maryland
The court drew a sharp line: viewing a screen saver that appears when you physically open a flip phone is not the same as scrolling through photos, messages, or call logs. The first falls within plain view; the second requires a warrant.
Locked Phones, Passcodes, and Biometrics
Even with a warrant, police often face a locked phone, and forcing a suspect to unlock it raises a separate constitutional question under the Fifth Amendment’s protection against compelled self-incrimination.
Federal courts have generally held that forcing someone to reveal an alphanumeric passcode is “testimonial” because it requires the person to disclose the contents of their mind, and is therefore protected by the Fifth Amendment.4Congressional Research Service. Constitutionality of Compelled Decryption Divides the Courts
Biometric unlocks like fingerprints and face scans have been treated differently. The government’s position has been that physically pressing a suspect’s finger to a scanner is more like appearing in a lineup than like giving testimony, and therefore falls outside Fifth Amendment protection. In the 2025 case of United States v. Brown, however, the D.C. Circuit drew a distinction between physically forcing someone’s finger onto a phone and instructing someone to unlock it themselves. When the defendant was told to open the phone rather than having their finger pressed to it, the court found the act of compliance was itself testimonial. How officers phrase their requests when seeking biometric access has become a critical factor.
What Riley Doesn’t Cover: Location Data From Carriers
Riley protects the data on the phone in your pocket. Records the carrier holds about where your phone has been are a separate question, answered in Carpenter v. United States in 2018. In a 5-4 decision, the Supreme Court held that the government needs a warrant supported by probable cause before obtaining historical cell-site location records that track a person’s movements over time.5Justia U.S. Supreme Court Center. Carpenter v. United States, 585 U.S. ___ (2018)
The Court rejected the government’s argument that people forfeit their privacy interest in location data simply because a third party (the cell carrier) collects it. Chief Justice Roberts wrote that cell-site records hold “the privacies of life” for many Americans, and emphasized the “deeply revealing nature” of this data, its comprehensive reach, and the fact that carriers collect it automatically whether the user knows it or not.6Supreme Court of the United States. Carpenter v. United States, No. 16-402 (2018)
How to Challenge a Warrantless Phone Search
If police searched your phone without a warrant and used what they found against you, the primary tool is a motion to suppress. The motion asks the court to exclude evidence obtained through a constitutional violation, and it flows from the exclusionary rule, a judicial doctrine rooted in the Fourth Amendment that bars the government from using unlawfully obtained evidence at trial.7Constitution Annotated. Amdt4.7.1 Exclusionary Rule and Evidence
Timing is not a technicality. In federal courts, motions to suppress are governed by Rule 41(h) of the Federal Rules of Criminal Procedure. In Maryland, Rule 4-252 requires a defendant who wants to suppress evidence from an unlawful search to file a written motion within 30 days of either the appearance of counsel or the defendant’s first court appearance, laying out specific factual and legal grounds for exclusion.8Maryland Courts. Sinclair v. State, No. 43 (2015)
The Sinclair case shows what happens when that deadline slides. Sinclair’s attorney filed a bare-bones “omnibus” motion, later withdrew it without prejudice, and then made an oral motion to exclude the phone evidence on the morning of trial, seven months later. The Maryland Court of Appeals found this fell far short of what the rules required, and without a showing of good cause for the delay, the challenge was waived. Most suppression efforts fail in practice not on the constitutional merits but on missed deadlines and procedural missteps.9Legal Information Institute. Motion to Suppress
Civil Suits Under Section 1983
Beyond suppression in a criminal case, a person whose phone was unconstitutionally searched may have a civil remedy under 42 U.S.C. ยง 1983, which allows lawsuits against state and local officials who violate constitutional rights while acting in their official capacity. These cases face a steep obstacle: qualified immunity, which shields officers from personal liability unless the unconstitutionality of their specific conduct was already clearly established by existing precedent at the time. The standard is demanding. The law must have placed the wrongfulness of the officer’s actions “beyond debate,” protecting all but the plainly incompetent or those who knowingly violate the law.10FBI Law Enforcement Bulletin. Qualified Immunity Today
If you believe your phone was searched without a warrant, the most useful step is to tell your defense attorney immediately, in writing, with as many specifics as you can recall: when, where, which officer, what they did with the phone, and what they saw. That record is what a timely suppression motion is built on, and the clock starts running earlier than most people expect.