A fire in a church in Castrop-Rauxel in the Ruhr area caused property damage of around 250,000 euros.
After initial investigations, negligent arson can be assumed, the police said on Tuesday.
The fire in the Church of the Redeemer was believed to have been caused by a stove in the kitchen that was switched on.
The fire was discovered late Monday afternoon.
Recklinghausen - Nobody was injured by the fire.
dpa