Robert Downey Jr., 36, had traces of cocaine in his system when he was arrested last month, authorities said Thursday. The Associated Press reports that the urine test of the “Ally McBeal” costar revealed no other drugs in his system, said Lt. Dave Tankenson of the Culver City Police Department. Downey submitted to the test voluntarily, reports AP. “It will be up to the DA’s office on what charges to file,” Tankenson said. “But we are recommending he be charged with a misdemeanor of being under a controlled substance.” Downey, who has returned to rehab, is due in court on Tuesday to face what police say will be a charge of being under the influence of a controlled substance. He could be sent to jail for up to a year if found guilty. On May 24 he also faces a more serious court case on charges of possessing cocaine and the prescription drug Valium. Those charges stem from his arrest in a Palm Springs hotel room last November.