Arizona Gov. Jan Brewer said at a press conference that Obama told her that the FBI would be in charge of the investigation. But other law enforcement sources indicated that the Pima County Sheriff's Department is still leading the investigation with assistance from federal officials.
The FBI, the Pima County Sheriff's Office and U.S. Capitol Police are investigating, FBI Spokesman Paul E. Bresson told TPM in an e-mail.
The shooter has been identified as Jared Loughner, who has left a trail on the Internet including YouTube videos and a MySpace profile.
The FBI, like the U.S. Marshals Service which handles judicial security, falls under the purview of the Justice Department. A spokesman for the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) -- another agency that falls under DOJ's overview -- said that the agency is assisting with the investigation. A spokesman for Attorney General Eric Holder did not immediately respond to a request for comment.