HOUSTON — Houston police say a man is in custody for carjacking a postal worker’s mail truck.

Police say they the postal service was able to track the truck through a GPS device and when officers stopped him he tried back the truck into a patrol car and then jump from a window.

Authorities believe the man is tied to at least two other unsuccessful carjacking incidents Saturday in Houston, including one where he pulled a gun on the driver of a pickup truck but then walked away.

His gun eventually was identified as a pellet gun.

Beside state charges, the unidentified man could be facing federal charges because the carjacking involved a federal worker and vehicle.