One of the four Marines killed during Friday’s attack in Chattanooga may have been armed and could have exchanged fire with shooter Mohammad Youssef Abdulazeez, the Washington Post reported on Monday.

Marines are not authorized to carry personally owned firearms at the Navy Operational Support Center, the second location Abdulazeez attacked during his violent spree, and where all five military fatalities occurred. But the FBI recovered a pistol from the scene which may have been “privately owned and used by one of the Marines,” according to the Post. Investigators are reviewing forensics to determine if the pistol was used to fire at or wound Abdulazeez, who died during the violence.

Investigators found Abdulazeez in possession of numerous weapons, including a rifle, Smith & Wesson handgun and semiautomatic shotgun. The Glock currently being examined by the FBI was found near one of the dead Marines, the Post reported. A Navy Petty Officer also died during the attack.

The shooting at so-called “gun-free” military installations in Tennessee has prompted calls for a policy change.

Governors in Texas, Louisiana, Arkansas, Oklahoma, Indiana and Florida have ordered National Guardsmen to be armed, and Florida Gov. Rick Scott relocated recruiters to armories.

U.S. military officials have said security at recruiting and reserve centers will be reviewed, but the Army's top officer, Gen. Ray Odierno, said it's too early to say whether the facilities should have security guards or other increased protection.

The Associated Press contributed to this report