Updated

Only an anti-anxiety medication turned up in toxicology tests done on the body of the 19-year-old gunman who fatally wounded eight people before killing himself last month at a shopping mall in Nebraska.

The autopsy report on Robert Hawkins revealed diazepam in his system. The tranquilizer is better known by its market name, Valium.

Douglas County Attorney Don Kleine told the Omaha World-Herald in a copyright story Tuesday that authorities sometimes "see people who have abused drugs or alcohol to give them the ability to carry out their misdeed."

"In this case," Kleine said, "it doesn't appear he had abused either." His blood revealed only therapeutic levels of the medication.

The autopsy report also said Hawkins killed himself Dec. 5 by a single shot from his assault rifle from under his chin.

Before committing suicide, Hawkins went into the Von Maur store at Westroads Mall and took an elevator up to the third floor. There he opened fire, fatally wounding eight people. Five other people were hit by bullets or bullet fragments, injuring two seriously.

Investigators will try to find out whether Hawkins had a prescription for the Valium, Kleine said.