Stone thieves targeted two schools overnight.
And residents are being urged to be vigilant and report suspicions to the police if they see stone being stripped off school roofs.
Thieves stole the stone off part of the roof to Scapegoat Hill Junior and Infant School on School Road either last night or early today.
And thieves also attempted to make off with stone from the roof of Farnley Tyas First School, Butts Road, on the same night.
It is believed they targeted the Scapegoat Hill school sometime after 9pm on Wednesday, when a meeting finished, and 7am on Thursday - when the caretaker arrived.
The school says a 'truck load' of slates were taken with a few left behind in the playground.
Part of the roof that was affected covers a classroom, but the theft did not affect the school.
Meanwhile, Farnley Tyas First School was also targeted and Katie Howbridge, school bursar, said: “They took it off a small stone building which has a sloping roof. We think they must have been disturbed because most of the stone was neatly piled up at the side.
“It has damaged the roof felting though and we’re having to cover it with tarpaulin to keep it waterproof.
“People may have seen someone in a high-vis jacket and not suspected anything, but we want people to be vigilant. We won’t be doing work after 7pm so if there are people here after that time then contact the police.”
Anyone who saw anything suspicious around the two schools or with information about the stone theft should contact police on 101.
In unrelated investigations, police would like to speak to the people pictured in the image gallery below. The people pictured in the images may be witnesses as well as suspects. If you recognise anyone, contact police on 101 quoting the reference number on the image caption.