A large fire that devastated a derelict mill is being treated as arson, police have said.
The blaze at Proofings Mill in Hare Hill Road, Littleborough, Rochdale, at about 16:30 GMT on Saturday resulted in the partial collapse of the building.
Police are appealing for several teenagers seen leaving the mill at 16:10 to come forward.
No-one was injured in the fire and 12 properties near to the mill were evacuated as a precaution.
Sgt Richard Price, of Greater Manchester Police, said: "The scale of the fire was significant and it is astounding that no-one was injured in the blaze.
"The local community were disrupted by this incident and I'm hoping that someone in the crowd knows something about how the fire started."