Jared Loughner's Alleged Killing Spree: Personal, Political or Psychotic?

Jan. 10, 2011— -- In the wake of the Tucson massacre that left six dead and 14 wounded, the nation's eyes have turned to alleged shooter Jared Lee Loughner's YouTube videos for answers.

Loughner -- the 22-year-old charged with the attempted assassination of Rep. Gabrielle Giffords -- has refused to speak with investigators since allegedly opening fire at a political event Saturday.

Online videos with puzzling prose about government, terrorism and sleep, along with descriptions from people who knew Loughner, paint the picture of a once-friendly student who, over time, lost touch with reality. But Loughner's reported "obsession" with Congresswoman Giffords and frustration over political issues add complexity to an action most would consider insane.

"You don't have to be nuts to do this," said Dave Cullen, author of "Columbine" -- a book documenting the 1999 shooting at Columbine High School in Colorado. "You have to be troubled in some way."

According to Cullen, few killers are actually insane -- meaning they can't distinguish between what's real and what's imaginary. Rather, killers with political motivation, such as Timothy McVeigh, or a personal agenda, such as Eric Harris at Columbine, understand what they're doing even though others may not.

"[Loughner] could have had some personal animosity with Congresswoman Giffords, but more likely he had a problem with government and she, as his Congressperson, is a symbol of that," said Cullen.

A signed note found in a safe at the Tucson home he shared with his parents suggests Loughner planned his attack. And a form letter from Giffords' office thanking him for attending an event similar to Saturday's "Congress on your Corner" implies the two had met before.

But based on Loughner's past -- including several run-ins with campus police and a request for clearance by a mental health professional from Pima Country Community College -- mental illness seems likely, Cullen said.

Theodore Kaczynski, the so-called Unabomber, was ultimately diagnosed with paranoid schizophrenia -- a condition marked by delusional, mistrustful thoughts, according to the National Institutes of Health.