The State Fire Marshal's office has ruled one of Tuesday's fires on National Road as arson.
Spokesman Shane Cartmill says investigators have determined that the fire at a trailer home at 5971 National Road was intentionally set.
No one was home at the time of the fire which broke out just before 5:00 a.m. Tuesday.
Cartmill says a second fire reported about 10 minutes later at vacant house at 6130 National Road has not been ruled arson at this time but is likely due to the close proximity to the other fire.
No one was injured in either fire.
The investigations are being conducted by the State Marshal's Office, the Muskingum County Sheriff's Office and the Falls Township and National Trails fire departments.