The 22-year-old former community college student suspected of opening fire on 18 people and killing six at a community political event in Tucson, Ariz., had "kind of a troubled past," the local sheriff announced.
Law enforcement officials have arrested and are questioning Jared Lee Loughner, who is suspected of orchestrating the shooting potentially with an accomplice, reports CNN.
Loughner is said to have shot Congresswoman Gabrielle Giffords in the head with a semi-automatic handgun at close range, according to a statement by the Pima County Sheriff's Department.
Loughner posted online commentary about government "mind control," illiteracy and currency systems on his YouTube channel.
He has had several contacts with law enforcement and made prior threats. "There's reason to believe this individual may have a mental issue," according to Pima County Sheriff Clarence Dupnik.