Police in Derry say they are treating a fire at a flat yesterday as arson.
Extensive damage was caused to the property on the Dungiven Road which broke out at around 6:45pm.
No injuries were reported.
Detective Sergeant Gingell says they are investigating the fire as arson with intent to endanger life.
They have thanked the member of public who raised the alarm and says had it not been for their actions, and the swift response from the fire service, it could have been a very different outcome.
Anyone who has any information is asked to come forward.