A police union is calling on Congress to investigate whether a tactical team from the U.S. Capitol Police was turned away from the scene of last week's Naval Yard shooting.
The United States Capitol Police Labor Committee said it has spoken to officers and was told a containment emergency response team -- known as CERT -- was told to leave.
"They were prepared to risk their lives to save the lives of the shooter's victims, but were prevented from doing so," labor committee Chairman James Konczos said in a statement. "It is impossible to say how the outcome would have been different if the CERT team had been permitted to respond."
Twelve people were killed during the rampage by gunman Aaron Alexis, who also was killed during a shootout with other law enforcement officers.
The specially trained U.S. Capitol Police unit was told to return to its position at the U.S. Capitol by a watch commander, CNN learned last week.
U.S. Capitol Police Chief Kim Dine ordered a police board review team to look into the the allegations a team was diverted from the shooting scene. That report is due back by October 21.
The union's labor committee noted Dine's move but wants Congress to take a separate look.