An off-duty Fort Worth police officer is on restricted duty after being arrested in Grand Prairie on Sunday on suspicion of drunken driving. The Fort Worth Police Department said Tuesday that officer W. Nash was arrested by Grand Prairie police just after 8 p.m. and charged with driving while intoxicated. Fort Worth police did not release the officer’s first name or share details about what led to Nash being stopped by Grand Prairie police. After learning of his arrest, the department said the internal affairs unit began an internal administrative investigation. The FWPD also said Nash was placed on restricted duty and stripped him of all police authority while the ongoing criminal and administrative investigations continue. “The Fort Worth Police Department holds its officers to a high standard on and off duty; therefore, a thorough investigation to collect and review the facts and the circumstances of these allegations will be conducted,” the department said in a statement. Fort Worth police said Nash started with the department 18 years ago and was most recently assigned to the Patrol Bureau.