Updated at 6:40 p.m. ET
The man who 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.
On Friday afternoon, Bedell's parents released a statement saying his actions were caused by mental illness, not a defective character, reports CBS National Security Correspondent David Martin.
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.
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.
Hill also said Bedell's parents found an e-mail from their son that indicated he had bought a gun. They asked Hill to help them find Bedell and get him assistance.
The 36-year-old Bedell returned to his parent's home Jan. 18, telling them "not to ask any questions" about where he had been. But he left after that, and his parents didn't know where he went.
Little is known about his trip east, but authorities know he spent time in Reno, where Washoe County Sheriff Mike Haley said he was arrested on Feb. 1 with two ounces of marijuana in his car but no weapons.
The Bedell family put out a statement Friday saying they were "devastated as a family by the news."
"We may never know why he made this terrible decision," the statement said. "One thing is clear though - his actions were caused by an illness and not a defective character."
Investigators were trying to unravel a bizarre series of Internet postings that suggested Bedell was fascinated with conspiracy theories, computer programming, libertarian economics and the science of warfare.
Bedell was also apparently consumed by a get-rich-quick scheme which he advertised on YouTube, Martin reports.
On a Wikipedia page linked to Bedell, a user by the name JPatrickBedell revealed ill feelings toward the government and the armed forces and made reference to another conspiracy theory.
JPatrickBedell wrote that he was "determined to see that justice is served" in the death of Marine Col. James Sabow, who was found dead in the backyard of his California home in 1991. The death was ruled a suicide but the case has long been the source of theories of a cover up. Sabow's family has maintained that he was murdered because he was about to expose covert military operations in Central America involving drug smuggling.
Crimesider: James Sabow's Death a Government Cover-up?
Curiously, Bedell also proposed in 2004 that the Pentagon fund his own research on smart weapons. The 28-page proposal outlined his idea for DNA nanotechnology research that might "provide significant new capabilities for the Department of Defense and the individual warfighter."
That document is the first tangible link to surface connecting Bedell and the Pentagon.
On the day of the attack, Bedell left his green, 12-year-old Toyota in a nearby mall parking garage.
The six-foot tall, blue-eyed software devotee approached the Pentagon entrance Thursday evening wearing a jacket, dress shirt and pants, seeming like any other end-of-the-day commuter.
Bedell, the officials say, opened fire with a 9 mm handgun just five feet from the nearest officer, Marvin Carraway. Fellow officer Jeffrey Amos ran out of a nearby guard booth to confront Bedell, as did a third, unidentified officer. All three officers gave chase and fired at Bedell, who was struck in the head and left arm.
The assault at the very threshold of the Pentagon - the U.S. capital's ground zero on Sept. 11, 2001 - came four months after a deadly attack on the Army's Fort Hood, Texas, post allegedly by a U.S. Army psychiatrist with radical Islamic leanings.
CBS News correspondent Bob Orr reports investigators are confident that Bedell acted alone, and there is no indication he was connected to any terrorist organizations or under any terrorist influences. That said, police were keeping an open mind and looking into the possibility that Bedell may have been inspired by the Fort Hood attack.
"It's very hard for the government to ferret-out and prevent individuals acting on their own," CBS News security analyst Juan Zarate said on "The Early Show". "The pentagon officers need to be commended. Security worked exactly as it should."
"There's a societal responsibility here," said Zarate, suggesting family members and friends must try and recognize and report signs of a personality capable of causing harm.
"I don't think we can rely on the FBI, the government" to identify and thwart such attacks, Zarate added.
Hatred of the government motivated a man in Texas last month to fly a small plane into a building housing Internal Revenue Service offices, killing an IRS employee and himself.
The shooting resembled one in January in which a gunman walked up to the security entrance of a Las Vegas courthouse and opened fire with a shotgun, killing one officer and wounding another before being gunned down in return fire.
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