The California man who was killed in a shootout with Pentagon police had a history of mental illness and had become so erratic that his parents reached out to local authorities weeks ago with a warning that he was unstable and might have a gun, authorities said Friday.

It's still unclear why John Patrick Bedell opened fire Thursday at the Pentagon entrance, wounding two police officers before he was fatally shot. The two officers were hospitalized briefly with minor injuries.

Bedell was diagnosed as bipolar, or manic depressive, and had been in and out of treatment programs for years. His psychiatrist, J. Michael Nelson, said Bedell tried to self-medicate with marijuana, inadvertently making his symptoms more pronounced.

"Without the stabilizing medication, the symptoms of his disinhibition, agitation and fearfullness complicated the lack of treatment," Nelson said.

His parents reported him missing Jan. 4, a day after a Texas Highway Patrol officer stopped him for speeding in Amarillo, according to the missing person's report. Bedell told the highway patrolman he was heading for the East Coast, and the officer used Bedell's phone to call his mother, Kaye Bedell, because he seemed disheveled and out of sorts.

Family friend Reb Monaco said Kaye Bedell asked the officer to take him to a mental health facility, but that the son refused. The patrolman let Bedell go with a warning. The next day, Kaye told deputies in California that her son had no reason to travel to the East Coast because he had no friends or family there and she and her husband were worried about his mental state, San Benito County Sheriff Curtis Hill said.