The fire that killed a West Virginia Air National Guard firefighter early Sunday was arson, the state firefighter said.
The firefighter, whose name has not yet been released, responded to help with a fire in Martinsburg, in the northeast corner of the state, the NBC subsidiary WSAZ of Huntington reported.
Officials said there were two arsons early Sunday, one at 2 a.m., in which the firefighter died, and one earlier around 1:30 a.m. in neighboring Jefferson County.
The firefighter tweeted that the fires had started around unused structures 3 miles apart.
The marshal has not yet publicly identified any suspects and has offered a reward for information.
The deceased firefighter was assigned to the 167th Airlift wing in Martinsburg. It was unclear if there were any additional injuries.