Terence Crutcher, shot by Oklahoma police, had PCP in blood

Officer Betty Shelby (L) shot and killed Terence Crutcher, pictured with his twin sister

An unarmed man shot dead by a police officer in Tulsa, Oklahoma, last month had the hallucinogenic drug PCP in his system, say officials.

Terence Crutcher, 40, had "acute phencyclidine intoxication" when he was fatally shot on 16 September, according to a medical examiner.

Officer Betty Jo Shelby shot Crutcher, who is black, once after finding his car broken down on a city street.

She has been charged with first-degree manslaughter.

Officer Shelby joined the Tulsa Police Department in December 2011

Officer Shelby, who is white, said Mr Crutcher disobeyed her commands, but prosecutors say she "reacted unreasonably" and unnecessarily escalated the situation.

The Tulsa World reports that an Oklahoma State Medical Examiner's Office toxicology report found Mr Crutcher had 96 nanograms per millilitre of phencyclidine, or PCP, in his bloodstream.

Police confirmed last month to the newspaper that a vial of the drug had been found in Mr Crutcher's car.

But Crutcher family lawyer Benjamin Crump had said: "Let us not be thrown a red herring and to say because something was found in the car that is justification to shoot him."

Police footage from a helicopter and a patrol car's dashboard camera shows Mr Crutcher walking away from Officer Shelby with his arms in the air.

But the clip offers no clear view of the moment Officer Shelby shot him in the chest.

According to medical literature, PCP, also known as Angel Dust, can induce feelings of euphoria, omnipotence and combativeness.