Jared Lee Loughner, the key suspect in the shooting attack that critically wounded Arizona Jewish Congresswoman Gabrielle Giffords on Saturday, listed Mein Kampf and the Communist Manifesto as two of his favorite books.
On his YouTube and MySpace pages, the 22-year-old posted masses of anti-government ramblings on his MySpace page and on a YouYube account "Classitup10" that was linked to him.
The MySpace page, which was removed within minutes of the gunman being identified by U.S. officials, included a mysterious" Goodbye friends" message published hours before the shooting and exhorted to his friends: "Please don't be mad at me."
The YouTube account is still operational.
His exact motivation was not immediately clear. Federal law enforcement officials were poring over captured versions of the MySpace page and over uploaded Youtube videos.
Loughner, a Tucson resident, is currently being held in custody. Pima County Sheriff Clarence Dupnik described him as "unstable" but not "insane.
The sheriff told a news conference that the suspect was tackled to the ground after the shooting that left six people dead and 13 wounded.