FORT HOOD, Texas (AP) - A Texas congressman has identified the suspect in the shooting at Fort Hood as Ivan Lopez, an active military truck driver who was on duty when the shooting occurred.
Authorities say Lopez was an Iraq War veteran who was being treated for mental illness.
Within hours of the attack, investigators started looking into whether his combat experience caused post-traumatic stress.
U.S. Rep. Michael McCaul, chairman of the House Homeland Security Committee, said Wednesday's shooting happened at a medical center at the base.
A U.S. law enforcement official says four people, including Lopez, have died.
The official says reports circulating within the Justice Department indicate the shooter has died of what appears to be a self-inflicted wound.
Bell County Sheriff's Office Lt. Donnie Adams says the sheriff's office dispatched deputies and troopers from the Texas Department of Public Safety to the nearby Texas Army post.
Fort Hood ordered everyone at the base to "shelter in place." That lockdown has since been lifted.
The Army post was the scene of a mass shooting in 2009. Thirteen people were killed and more than 30 wounded.