TUCSON, Ariz. -- A man accused in the deadly Tucson shooting rampage that killed six people and wounded 13 others including Arizona congresswoman Gabrielle Giffords researched lethal injections, solitary confinement and political assassinations in the days before the attack, a newspaper reported Wednesday.
A source close to the investigation into 22-year-old Jared Loughner told The Washington Post that a review of his computers turned up the Internet searches. Officials with the FBI and Justice Department contacted by The Associated Press declined to comment Wednesday on the Post's story or verify any part of it
Loughner's alleged actions could help prosecutors as they begin the process of pursuing charges that could lead to the federal death penalty.
He was indicted last week on federal charges of trying to assassinate Giffords and trying to kill two of her aides -- Ron Barber and Pam Simon -- in the Jan. 8 shootings outside a Tucson supermarket during a meet-and-greet event with the three-term Democratic congresswoman's constituents.
An earlier criminal complaint also had charged Loughner with murder in the deaths of Giffords' aide Gabe Zimmerman, 30, and U.S. District Judge John Roll, 63.
Loughner pleaded not guilty Monday during a hearing in Phoenix and remains in federal custody.
Law enforcement sources familiar with the investigation told the Post that Loughner surfed the Internet on his computer in the weeks and days before the shooting rampage.
The newspaper said Loughner pulled up several Web sites about lethal injections and solitary confinement in prison and also viewed Internet sites about political assassins.
The Post said prosecutors hope to use the information they have found on Loughner's computer, along with notes seized in his home, to indicate that he wasn't insane and knew right from wrong. They have turned over to the defense the information they obtained from the computer, as well as discs containing about 250 interviews conducted by investigators, according to the newspaper.
Prosecutors said Loughner also is likely to face state charges in the shootings of the other non-federal employees who were killed and injured. His next court hearing is March 9.
Giffords, 40, is recovering from a gunshot wound to the head. She was moved Wednesday out of intensive care at a Memorial Hermann hospital in Houston.