Austin Seferian-Jenkins was high, drunk AND speeding when he was arrested for DUI last week ... this according to cops in new police docs obtained by TMZ Sports.
Oh, and cops also say he didn't have the ignition interlock device installed in his car, stemming from a court order from a previous DUI.
A Gig Harbor PD officer claims the NFL free agent was doing 48 MPH in a 30 in Gig Harbor, Wash. on March 9 at around 1 AM ... when the former Tampa Bay Buccaneer began driving erratically.