Most people keep a massive amount of personal information on their phones, and evidence taken from cellphones is increasingly used in criminal investigations. However, your phone is your property, and police can’t just take your phone from you in any given situation.

Generally, police need a warrant to seize and search your cellphone — but there are exceptions.

A police officer still has a right to ask to see your phone, and an officer may even ask you to unlock your phone and show it to the officer. However, you can decline to do that in the absence of a warrant, then call a criminal defense attorney. Under the Fifth Amendment to the Constitution, you cannot be compelled to unlock your cellphone for police, as doing so could be self-incriminating.

In certain emergency situations, though, a police officer may not need a warrant to look at your phone. For example, if the officer believes your phone contains information related to a bomb threat or a child abduction, the officer may not need a warrant. Essentially, if the officer has probable cause to believe a crime has been committed, or if you are arrested, your cellphone may be seized by police.

Because legal issues regarding search and seizure are constantly evolving, you should speak with a criminal defense attorney before giving consent to police to search your phone. If a search warrant is granted to allow a search of your phone, you should have a lawyer investigate whether police exceeded the scope of the warrant.

For more on that, please see our previous post, “Understanding the scope of search warrants.”