A senior U.S. official in Washington isn't ruling out the possibility that the alleged Fort Hood shooter had ties to radical groups, but isn't saying whether there's evidence to back it up.
Officials now say a 13th person has died in yesterday's rampage in Texas and 30 were wounded. Authorities at first thought one of the dead was the shooter, accounting for a delay in identifying him.
Lt. Gen. Robert Cone, Fort Hood's base commander, told CBS's "The Early Show" that the alleged shooter is rumored to have said during the shooting, but was unable to confirm that information.
As military officials try to piece together what may have pushed Army psychiatrist Maj. Nidal Malik Hasan to turn on his comrades, the wounded suspect is on a ventilator, unconscious and under guard in a hospital.
Law enforcement officials say Hasan came to their attention at least six months ago, because of Internet postings about suicide bombings and other threats. It's not yet certain he authored the posts.
More coverage of the tragedy at Fort Hood:
Store Video May Show Ft. Hood Shooter
Ft. Hood Suspect ID'd as Army Psychiatrist
Soldier Opens Fire at Ft. Hood; 13 Dead
Anti-Muslim Backlash Immediate
Sources: Hasan Web Posts Drew FBI Interest
Fort Hood Rampage Suspect Sill Alive
What was Shooter's Motive?
U.S. Army Base Violence Has Bloody History
Obama: Fort Hood Shooting "Horrific"
Fast Facts: Fort Hood
Tragedy at Fort Hood
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