The fire that killed a West Virginia Air National Guard fireman on Sunday morning was arson, the state fireman said.
The firefighter, whose name has not yet been released, was responding to a fire in Martinsburg, in the northeastern state, said NBC affiliate WSAZ of Huntington.
Authorities said there were two arson incidents on Sunday morning, one at 2 am, in which the fireman died, and one earlier, at around 1:30 am, in neighboring Jefferson County.
The fireman tweeted that the fires were caused by unused structures over 3 miles away.
The marshal had not yet publicly identified any suspects and was offering a reward in exchange for information.
The deceased firefighter was assigned to the 167th Airlift Wing in Martinsburg. It was not clear whether there were additional injuries.
