The state fire marshal's office says it is pursuing leads concerning the person or persons responsible.

The Delaware Office of the State Fire Marshal is investigating Thursday morning’s house trailer fire in Dover as an arson.

The blaze, reported shortly after 11 a.m., occurred in the unit block of East Pinewood Drive near South State Street. The Dover Fire Department responded to the call and arrived on the scene with an active fire.

State fire investigators were called to the scene to conduct the investigation. The fire was deliberately started inside the house trailer. Deputy fire marshals have developed significant leads and are pursuing those leads in an effort to make an apprehension.

Heavy fire damage was estimated at $30,000. One person was transported to the Kent General Hospital in stable condition for lacerations.