(CNN) -- It has been called the most popular rifle in America, and it briefly returned to the spotlight after Monday's shooting at the Navy Yard: the AR-15.
A U.S. law enforcement official said Monday that gunman Aaron Alexis unleashed a barrage of bullets using an AR-15, a rifle and a semi-automatic handgun. Authorities believed the AR-15 was used for most of the shooting, the official said. The news prompted Sen. Dianne Feinstein, one of the strongest proponents of a ban on assault weapons like the AR-15, to issue a statement the same day asking, "When will enough be enough?"
However, federal law enforcement sources told CNN Tuesday that authorities have recovered three weapons from the scene of the mass shooting, including one -- a shotgun -- that investigators believe Alexis brought in to the compound. The other two weapons, which sources say were handguns, may have been taken from guards at the Navy complex.
