Two flats have been left heavily smoke damaged following a bin fire.
It happened in flats at Waterloo Walk, in Sulgrave, Washington, at 6am on Friday.
A bin fire had caused smoke to filter into flats.
Two crews from Washington fire station and one from Birtley attended the call.
Watch manager Les Tough, of Washington station, said: “The bin fire was on the ground floor and affected two flats on the third floor.
“When we first got there we thought there was someone in one of the flats, so we sent four officers in, but it was empty.
“Both flats were fully smoke damaged and police are investigating.
“It could be malicious or accidental.”