Wyatt told police he had drunk a cup of tea spiked with hallucinogenic mushrooms and became convinced his close friend Taylor Powell was possessed.
According to an autopsy Powell,21, bled to death after his heart was ripped out.
The coroner said Powell had been alive when the organ was ripped out after his chest had been sliced open with a knife.
Wyatt told the police he thrown the heart into a fire along with other organs that he had removed from the body.
He told investigators he cooked the body parts because he was fearful Powell was still alive and he “needed to stop the Devil.”
Police had been called to the grisly scene after a third friend had witnessed a sudden mood change in Wyatt after they had all ingested wild mushroom tea.
Justin Davis told police he returned to the flat in Klamath, California, to find Wyatt naked and covered from head to toe in blood.