A cell phone can contain an extraordinary record of a person’s daily life. Text messages, photographs, emails, internet searches, location history, social media activity, financial information, contacts, and app data may all become potential sources of evidence during a criminal investigation.
For law enforcement agencies investigating crimes in Los Angeles, digital evidence can help establish relationships, timelines, locations, communications, and other details prosecutors may later attempt to introduce in court.
But police access to a phone or digital account is not unlimited. Both the Fourth Amendment and California law place significant restrictions on how government agencies may obtain and search electronic information.
When digital evidence plays an important role in a criminal case, the way investigators obtained that information can become just as important as what they found.
Police Generally Need a Warrant to Search a Cell Phone
Being arrested does not automatically give police permission to search through the digital contents of a person’s phone.
The U.S. Supreme Court addressed this issue directly in Riley v. California. The Court held that police generally must obtain a warrant before searching digital information stored on a cell phone seized during an arrest.
The ruling recognized that smartphones are fundamentally different from ordinary physical objects someone might carry in a pocket.
A modern phone can contain thousands of photographs, years of messages, browsing history, medical information, financial records, location history, and access to information stored remotely. Because of the enormous amount of private information a phone may reveal, the traditional rules allowing officers to search certain physical items following an arrest do not automatically extend to digital data.
Police can generally seize and secure a phone while pursuing lawful investigative steps. Searching the information inside it, however, ordinarily requires additional legal authority.
What a Cell Phone Search Warrant May Cover
When investigators believe a phone contains evidence of a crime, they may seek a search warrant authorizing access to particular types of digital information.
Depending on the investigation, officers may seek:
- Text messages and messaging app conversations
- Photographs and videos
- Call records
- Contacts
- Emails
- Internet browsing history
- Location information
- Social media activity
- Notes and documents
- App data
- Financial or transaction information
- Files stored on the device
A warrant should not simply function as blanket permission to search every piece of information associated with a person.
California’s Electronic Communications Privacy Act requires warrants for electronic information to describe the information sought with particularity. When appropriate, that can include specifying relevant time periods, accounts, applications or services, and categories of information.
Those limitations can become important when investigators obtain large amounts of data but only a portion of it appears connected to the suspected offense.
California’s Electronic Communications Privacy Act
California provides additional statutory protections for electronic information through the California Electronic Communications Privacy Act, commonly called CalECPA.
The law covers both electronic communications and information generated or stored by electronic devices. Its definitions encompass information such as communications, IP addresses, and current or previous device locations.
Under Penal Code Section 1546.1, government entities generally may not access electronic device information or compel certain electronic communication information unless one of the circumstances authorized by the statute applies. Those circumstances can include a warrant, specific consent from an authorized possessor, certain emergency situations, and other specifically identified exceptions.
A 2026 California Court of Appeal decision discussing CalECPA reiterated that accessing electronic device information is generally restricted unless law enforcement is acting under one of these statutory exceptions.
For a Los Angeles criminal defense attorney reviewing digital evidence, that means the analysis may involve both constitutional protections and California’s specific electronic privacy laws.
Text Messages and Messaging Apps as Criminal Evidence
Text messages are among the most common forms of digital evidence used in criminal cases.
Investigators may argue that messages establish intent, show communication between alleged participants, document a transaction, demonstrate someone’s knowledge of an event, or help construct a timeline.
Messages can potentially come from several sources.
Police may obtain them directly from a phone, from another participant in the conversation, through information supplied by a service provider, or through other devices and accounts connected to the communication.
But a screenshot or isolated message does not necessarily tell the entire story.
Context can matter significantly. A defense attorney may examine the surrounding conversation, dates and times, who had access to the device or account, whether messages were deleted or incomplete, and whether prosecutors can reliably establish who actually sent a particular communication.
The legal question of whether investigators obtained the information properly is separate from the factual question of what the communication actually proves.
Photos, Videos, and Metadata
A photograph can reveal much more than the image itself.
Digital files may contain metadata identifying when a photograph was created, information about the device used, and potentially other technical details. Investigators may also compare photographs with physical locations, other devices, witnesses, or information gathered during an investigation.
Videos can similarly provide timestamps, voices, surroundings, or other details prosecutors may attempt to connect to alleged criminal activity.
However, digital evidence still must be evaluated carefully.
Important questions can include whether the file was edited, transferred between devices, downloaded from another source, or created by someone other than the defendant. The presence of an image on a device does not necessarily establish who created it, why it was saved, or how it reached the device.
These issues can become particularly important when multiple people had access to a phone, computer, account, or cloud storage service.
Location Data Can Reveal a Person’s Movements
Phones continuously interact with networks, apps, and services that may generate information about where a device has been.
That information can become extremely valuable to investigators attempting to place someone near a particular location.
In Carpenter v. United States, the U.S. Supreme Court held that obtaining an extended record of historical cell-site location information constituted a Fourth Amendment search, recognizing the significant privacy interests involved when the government can reconstruct a person’s movements over time.
The law surrounding digital location information has continued to develop.
In 2026, the Supreme Court addressed Location History data obtained from a third-party technology company in Chatrie v. United States. The Court concluded that law enforcement conducts a search when it obtains this type of cell phone location information from a technology company because individuals have a reasonable expectation of privacy in records revealing their phone’s location. The Court left additional questions about the reasonableness and particularity of the warrant for further proceedings.
These cases illustrate how rapidly advancing technology continues to shape Fourth Amendment law.
What About Cloud Accounts and Information Held by Tech Companies?
Not every piece of digital evidence is physically stored on the phone itself.
Emails, photographs, backups, account information, messages, and other records may be stored remotely by technology companies or online service providers.
California law specifically addresses government efforts to obtain electronic communication information from service providers. Penal Code Section 1546.1 generally requires law enforcement to rely on authorized legal procedures, including warrants in criminal investigations, subject to the exceptions contained in the statute.
This means an investigation can involve several different sources of digital evidence.
Police might physically possess a suspect’s phone while separately requesting information associated with an online account. Each method of obtaining information can raise its own legal questions.
A defense review may therefore examine not just one search warrant, but multiple warrants, provider requests, account records, and digital forensic reports.
Consent Can Change the Analysis
A search warrant is not the only way investigators may lawfully gain access to electronic information.
California law permits access to electronic device information in certain circumstances when the authorized possessor gives specific consent.
However, consent can create its own legal questions.
Who actually had authority over the device? What exactly did that person agree to? Was the consent voluntary? Did investigators stay within the scope of the permission they were given?
The California Court of Appeal considered consent and CalECPA in People v. Anderson in 2026. The case involved police accessing a phone after obtaining consent from another individual, and the court examined both CalECPA and the application of the good-faith exception to suppression.
Digital evidence cases can therefore turn on facts that may appear minor at first, including who owned or possessed a device and what officers were told before searching it.
Emergency Exceptions to the Warrant Requirement
There are circumstances in which law enforcement may access electronic information without first obtaining a warrant.
California law includes an emergency exception when a government entity in good faith believes access is necessary because of an emergency involving danger of death or serious physical injury. The statute also imposes procedures requiring law enforcement to seek subsequent judicial approval in qualifying situations.
Federal constitutional law similarly recognizes exigent circumstances that can sometimes justify warrantless action.
These exceptions are designed for genuine emergencies rather than as a general alternative to obtaining a warrant.
When prosecutors rely on an emergency justification, the particular facts known to officers at the time can become important in determining whether the warrantless access was lawful.
Digital Searches Can Produce Enormous Amounts of Information
One of the challenges created by modern electronic searches is sheer volume.
A physical search might uncover several documents or objects. A digital search can potentially expose thousands of messages, photographs, files, account records, and location points spanning months or years.
California law attempts to address that concern by imposing particularity requirements on electronic warrants. Penal Code Section 1546.1 also states that information obtained through execution of an electronic warrant that is unrelated to the warrant’s objective must generally be sealed and restricted from further review, use, or disclosure unless additional legal requirements are satisfied.
This can make the precise wording of a digital search warrant especially important.
A defense attorney may examine the dates covered by the warrant, the applications investigators were permitted to search, the type of evidence they were looking for, and whether investigators expanded their search beyond those boundaries.
Authenticating Digital Evidence
Even when electronic information was legally obtained, prosecutors still may need to establish that the evidence is what they claim it is.
For example, the existence of a message on a phone does not automatically prove who typed it. A social media account bearing someone’s name does not necessarily prove that person controlled every post or message associated with it.
Digital evidence may be evaluated alongside account records, witness testimony, device ownership, login information, surrounding communications, timestamps, or other evidence connecting the material to a particular person.
A defense investigation can therefore involve both constitutional questions about how the evidence was obtained and evidentiary questions about whether it can reliably be attributed to the defendant.
Challenging Digital Evidence in a Los Angeles Criminal Case
When electronic evidence was obtained through an allegedly unlawful search, the defense may seek to prevent prosecutors from using it.
California Penal Code Section 1538.5 permits defendants to move to suppress tangible or intangible evidence obtained through an unreasonable search or seizure. Grounds can include warrantless searches as well as searches involving defective warrants, lack of probable cause, evidence outside the warrant’s authorization, or unconstitutional execution of the warrant.
A digital evidence challenge may require reviewing:
- Search warrants and supporting affidavits
- The specific information authorized by the warrant
- Digital forensic extraction reports
- Provider records
- The dates and accounts covered by the search
- Officer reports and body-worn camera footage
- Consent forms or recorded statements
- Location records
- Chain-of-custody documentation
- The methods used to associate an account or device with the defendant
Because electronic investigations can generate enormous amounts of information, carefully tracing where each piece of evidence came from can be a significant part of the defense.
Los Angeles Criminal Defense and Digital Evidence
Cell phones have become one of the most powerful investigative tools available to law enforcement, but the information they contain also receives significant legal protection.
A phone seized during an arrest is not automatically an open book. Search warrants, California electronic privacy law, consent requirements, location-data protections, and constitutional limits can all affect whether digital evidence was legally obtained and whether prosecutors may use it.
If digital evidence plays a role in criminal charges against you in Los Angeles, Simmons & Wagner can review how investigators obtained the information, what the warrant authorized, and whether there may be grounds to challenge the evidence.
Contact Simmons & Wagner to discuss your case and learn more about your legal options.