An unarmed man who was fatally shot last month by a police officer in Tulsa, Okla., had a high level of the drug PCP in his body, a coroner reported on Tuesday, confirming what the police surmised at the time.

Officer Betty Jo Shelby, 42, has been charged with manslaughter in the death of Terence Crutcher on Sept. 16. Video of the shooting showed Mr. Crutcher, 40, walking away from her with his hands raised, and then stopping beside his sport utility vehicle and lowering his hand just before she fired a single shot from several feet away.

The police said that Mr. Crutcher, who was black, had stopped his vehicle in the middle of a road and gotten out, leaving the engine running. He was talking nonsensically and not responding to commands from the officer, who is white. After the shooting, the police said, officers found in the vehicle a vial of phencyclidine, known as PCP, a drug that can induce powerful hallucinations.

Mr. Crutcher’s was one in a series of highly publicized deaths of black men at the hands of the police, which have prompted searing debates about the roles of race and law enforcement. The shooting sparked protests, which were overshadowed days later by much larger demonstrations in Charlotte, N.C., where another black man, Keith Lamont Scott, was fatally shot by an officer.