A 13-year-old boy died when he fell through the roof of a factory in Bradford, police have said.
Officers found the body after being called to reports of youths playing on top of the building in Allerton Road on Friday night.
The death has been reported to the coroner and a post-mortem examination is to take place on Saturday.
Police said there was not thought to be anything suspicious about the death but are appealing for witnesses.
Anyone who may have seen a group of youths in the area before the accident is asked to contact police.
A spokeswoman said officers were particularly appealing to a man who flagged down police to alert them to the boys on the roof.