Texas  |  Criminal Law

They would be required to show that they had probable cause to believe that evidence of a crime had led them to a person or persons who used that phone. The warrant is likely going to be open-ended, assuming that the surveillance is conducted within a reasonable amount of time after the issuance of the warrant (that is, the information is not stale) and that the ongoing investigation reveals evidence of criminal activity (so that the agency can build a case against new defendants if the investigation reveals criminal activity and additional parties/crimes). If that was the case, there would be no need to "extend the warrant". There is no obligation of a telephone service provider to disclose to a customer that their line is subject to law enforcement monitoring or an active warrant, for the same reason that an undercover police officer does not have to identify himself or herself if asked "Are you a cop?"