The suspect in the deadly shootings in Colorado had an AR-15 assault rifle, a shotgun and two Glock pistols.
A federal law enforcement official says the suspect, identified by other federal law enforcement officials as James Holmes, also hurled a gas canister in the attack in a movie theater in the Denver suburb of Aurora, Colo. The official spoke on the condition of anonymity to discuss the ongoing investigation.
Officials believe Holmes killed a dozen people when he open fired in the crowded theater. He was wearing a gas mask during the attack.
Investigators from the Bureau of Alcohol, Tobacco, Firearms and Explosives, along with other local, state and federal law enforcement officials, are investigating the overnight attack.