The FBI has discovered a gun that it said could have been owned and used by one of the U.S. Marines who was killed during last week's shooting in Chattanooga, Tennessee, the Washington Post reported. Marines are not allowed to carry personally owned firearms while at the Navy Operational Support Center, where the shooting took place.

Investigators were using forensics to try and determine whether or not a 9 millimeter Glock, found near a victim's body, was used during the shooting, and if so, by whom. The weapon might have wounded the shooter, Mohammad Youssef Abdulazeez, officials said. The standard-issue military pistol is a 9 millimeter Beretta.

The Pentagon restricted who was allowed to carry weapons at domestic military facilities in the 1990s, and currently allows only military police to carry weapons most of the time. After the shooting in Chattanooga — in which a shooter gunned down four Marines and one U.S. Navy Petty Officer at a reserve center and recruiting office — a public discussion has begun about whether or not military personnel at bases or other facilities should be armed. In response, some states were allowing personnel at National Guard facilities, which fall under control of the respective state's governor, to be armed. Those states include Oklahoma, Arkansas, Louisiana, Texas, Utah, Indiana and Florida. 

"I will not permit our citizen soldiers to remain unable to defend themselves," said Indiana Gov. Mike Pence, who authorized National Guard troops in his state to carry weapons on base, CBS News reported.

In the past, there have been several other cases where military personnel have been killed at military facilities. In June 2009, one solider was shot and killed and another was injured outside a military recruiting center in Little Rock, Arkansas. In October 2013, a Tennessee National Guard recruiter shot and wounded three people in the Millington, Tennessee armory, the Associated Press reported.  

“Long before the Chattanooga attack, we had been working to clarify a post commander’s authority to allow carrying of personal firearms,” said Sen. John McCain, chairman of the Senate Armed Services Committee, and Rep. Mac Thornberry, chairman of the House Armed Services Committee, the Washington Post reported. “This year’s National Defense Authorization Act will reflect that work. Together, we will direct the Pentagon to end the disconnect between the threats our war fighters and their families face and the tools they have to defend themselves.”