POTOMAC HEIGHTS, Md. (AP) — Investigators say they believe a fire at a vacant mansion on the Potomac River in Charles County was intentionally set.

The State Fire Marshal’s Office says an incendiary device was used to start the fire in the three-car garage of the home in Potomac Heights.

Investigators say the home was last owned by Seed Faith International Church and that the former pastor, Robert Freeman, lived there. Freeman was sentenced in 2012 to more than two years in prison after he pleaded guilty to obstructing bankruptcy proceedings. The home was valued at $1.75 million at the time of his sentencing.

The fire broke out Sunday afternoon, and it took firefighters nearly three hours to bring it under control. One firefighter was treated for heat-related illness.

Investigators haven’t named any suspects.

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