A man found dead in a parked car in Northern California has been identified as former San Diego Chargers quarterback Jesse Freitas, authorities said Wednesday.

Petaluma police Lt. Dan Fish said an investigation found no indication of trauma or foul play. An autopsy was performed Tuesday but authorities were awaiting the results from toxicology tests before making a final determination, Fish said.

Freitas, who ran into legal troubles in recent years, was found unresponsive in his vehicle Sunday by a family walking in a Petaluma neighborhood, The Santa Rosa Press Democrat reported.

Freitas, 63, was fully clothed and on his back with his left arm across his chest, as if he had been lying down to take a nap or rest.

Freitas apparently had come to the area to meet with a real estate agent in the neighborhood but missed the appointment, Fish said.

"It's very likely he was there waiting for an appointment with a real estate agent and he laid down in back of (the) car with (the) door open and died from an unknown cause," he added.

Freitas grew up in San Mateo and was drafted by the Chargers in 1974. Over the next two seasons, he played in 13 games and threw eight touchdowns as a backup to Hall of Famer Dan Fouts.

After those pro football days, Freitas' behavior was at times erratic and he was arrested for crimes including petty theft, hit-and-run, trespassing and violating restraining orders. His family has said he struggled with mental illness.

Freitas' family agreed to the coroner's suggestion to have Freitas' brain analyzed to see if he was suffering from traumatic shock that occurs from football injuries, said the player's younger brother, James Freitas, of Rancho Penasquitos in Southern California.