More than 80 firefighters tackled a major fire at a disused school in Oxfordshire.
Eyewitnesses said they saw two young people on the building
The Neithrop School in Preston Close, Banbury, was badly damaged in the fire which broke out at about 1900 BST on Tuesday, but no one was injured.
Some eye witnesses say that at one stage they saw two young people on top of the building.
The fire, which police are treating as suspicious, was visible across much of the town and more than 30 people raised the alarm by calling 999.
Nearby St Joseph's and Orchard Fields primary schools, which are on the same site, were not damaged by the fire and opened as normal on Wednesday morning.
An investigation into the cause of the fire has been launched and bulldozers were brought in to demolish parts of the building on Wednesday afternoon.
Police are appealing for witnesses to come forward.