A 12-year-old boy has died after falling through the roof of a disused building on an industrial estate.
Leon Hoyle was found by fire crews at Lune Business Park in Lancaster, Lancashire, at about 21:30 BST on Monday.
He was believed to have been playing with friends when he went through a corrugated roof panel, police said.
His family have been informed of his "tragic" death and are being supported by officers.
Det Insp Simon Dent, of Lancashire Police, said: "This is a tragic incident which has cost a young man his life and our thoughts are with his family and friends at this time."
He warned of the dangers of youngsters playing in disused buildings.
"We understand that youngsters find sites such as this interesting and want to explore them but, as this incident shows, there are potential dangers of entering abandoned buildings," he said.
"We hope parents will assist us by reinforcing that message to their children, especially during the school holidays."
He asked anyone with information about the incident to contact Lancashire Constabulary.