The police might be able to search the personal data on your phone, without a warrant, while you are on probation or parole. People on probation or parole usually have to adhere to certain terms and conditions (for example, attending counseling or agreeing to obey the law). One such condition is agreeing to warrantless searches by the police. If this is one of the terms of your probation or parole, then law enforcement can search your phone without a valid search warrant.