The Department of the Navy will posthumously award Purple Heart medals to four Marines and a sailor killed by a lone terrorist at the Navy Operational Support Center Chattanooga in July, according to a statement from Navy Secretary Ray Mabus.

Another Marine wounded in the shooting will also be awarded the Purple Heart.

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"Following an extensive investigation, the FBI and NCIS have determined that this attack was inspired by a foreign terrorist group, the final criteria required for the awarding of the Purple Heart to this sailor and these Marines," Mabus said in a statement. "This determination allows the Department of the Navy to move forward immediately with the award of the Purple Heart to the families of the five heroes who were victims of this terrorist attack, as well as to the surviving hero.".

The announcement comes hours after a news conference where the FBI director labeled the shootings an act of terror.

"We've investigated Chattanooga as a terror attack from the beginning," Director James Comey said, according to a report from Fox News. "The Chattanooga killer was inspired by a foreign terror organization. It's hard to entangle which particular source … there are lots of competing poisons out there."

The language Comey used was important because the law that governs the Purple Heart specifies that service secretaries can award the decoration in stateside incidents when the attacker was in contact with and inspired by foreign terror organizations.

Marine Gunnery Sgt. Thomas Sullivan, Lance Cpl. Squire K. Wells, Staff Sgt. David Wyatt and Sgt. Carson Holmquist were killed at Navy Operational Support Center Chattanooga on July 16, and Navy Logistics Specialist 2nd Class Randall Smith died July 18 from wounds sustained during the shooting. Marine Sgt. DeMonte Cheeley was shot in the leg and later recovered. All were nominated for Purple Hearts.

Comey said in November that the motivations of the Chattanooga shooter might never be made public, raising questions about whether the Navy would ever be in a position to award the Purple Heart to the families, which will now qualify for survivor's benefits associated with recipients of the decoration.

Benefits include burial in a National Cemetery free of cost and a monthly payment from the Veterans Administration to the families of service members killed in action.

Mabus said he hoped the award would comfort the families in some way.

"Although the Purple Heart can never possibly replace this brave sailor and these brave Marines, it is my hope that as their families and the entire Department of the Navy team continue to mourn their loss, these awards provide some small measure of solace," he said. "Their heroism and service to our nation will be remembered always."

Four U.S. Marines and one sailor were killed in a July attack in Chattanooga. (Credit: USA TODAY)