The firefighter was responding to a call early Sunday in Martinsburg.
The fire that killed a West Virginia Air National Guard firefighter early Sunday was arson, the state’s fire marshal said.
The firefighter, whose name has yet not been released, was responding as aid to a fire in Martinsburg, in the state’s northeast corner, NBC affiliate WSAZ of Huntington reported.
Officials have said there were two arson incidents early Sunday, one at 2 a.m., in which the firefighter died, and one earlier at around 1:30 a.m. in neighboring Jefferson County.
The fire marshal tweeted that the fires were set at unused structures about 3 miles apart.
The marshal had not yet publicly identified any suspects and was offering a reward for information.
The deceased firefighter was assigned to the 167th Airlift Wing in Martinsburg. It was unclear whether there were any additional injuries.