TUCSON, Jan. 12 (UPI) -- The suspect in the deadly weekend rampage at a political event in Tucson, Ariz., was a skilled marksman and "loves causing chaos," a friend said.
Jared Lee Loughner, 22, of Tucson faces federal charges in Saturday's shooting spree, in which U.S. Rep. Gabrielle Giffords was critically injured and U.S. District Judge John Roll, his law clerk Matthew Bowman and Giffords' staffer Gabriel Zimmerman were among the six dead. Thirteen others were injured.
Loughner took a cab to the shopping center where Giffords was holding a Congress on the Corner event.
A spokesman for Arizona Game and Fish said one of its agents pulled him over for running a red light a few miles away at about 7:30 a.m., not long before the shootings, The Arizona Republic reported. Jim Paxson said Loughner was driving a Chevrolet Nova, and the agent described him as polite, forthcoming and subdued.
Zane Gutierrez, 21, a friend of Loughner, described a pattern of strange beliefs and behavior.
"He was a nihilist and loves causing chaos, and that is probably why he did the shooting, along with the fact he was sick in the head," Gutierrez told The New York Times in an interview published Wednesday.
He said Loughner was obsessed with the meaning and importance of dreams. The suspect also read a book by the German philosopher Friedrich Nietzsche, "The Will To Power," and embraced ideas about the effects of nihilism, his friend said.
Loughner also "used the word hollow to describe how fake the real world was to him," Gutierrez said.
Loughner began working on his proficiency with a 9mm pistol, the same caliber weapon used in Saturday's attack, while in high school, his friend said.
"If he had a gun pointed at me, there is nothing I could do because he would make it count," Gutierrez said. "He was quick."
Law enforcement officials said police more than once went to the house Loughner shared with his parents.
Pima County Sheriff's Department spokesman Jason Ogan said he didn't know the nature of the calls or whether they involved Loughner or another member of the household, the Times said. He said the calls were being reviewed by legal counsel and would be released after the review was complete.