Youths seen in the grounds of a Swansea school hours before a devastating fire have been urged to come forward. The blaze at Penyrheol Comprehensive is being treated as suspicious after the main three-storey block was gutted.
It broke out at about 0100 GMT on Saturday, and police asked anyone near the school at the time or who may have seen something to contact them.
The 1,000-pupil school will be shut for seven to 10 days. One councillor said the community was in a state of shock.
Acting Det Insp Keith Morgan appealed to the youths to contact police and said: "Incidents such as this have a huge impact on the local community".
Among the sections destroyed were the science block, business studies, history and languages.
Firefighters managed to stop it spreading to a theatre and leisure centre, and water from the swimming pool was used to douse the flames.
Only the English and maths departments, which are sited in an annexe, were undamaged.
Swansea Council asked parents to make arrangements to look after their children while the school is shut.
The council said it would update parents on the closure and any alternative arrangements. It also asked them to check the council website and keep an eye on the news.
Phil Bailey, assistant chief officer for Mid and West Wales Fire Service, said more than 14 fire crews finally brought it under control at about 0500 GMT.
 Only English and maths areas survived the inferno unscathed |
"Once a fire is well developed it travels through the building quite quickly," he said. 'Heartbreaking'
Deputy head teacher Bruce Jones said it was "heartbreaking for the staff and pupils to see their work destroyed in this way".
Senior staff and the Swansea education chiefs were meeting on Saturday to draw up contingency plans for the pupils.
Mr Jones said the main aim was not to disrupt year 10 and 11 GCSE students' education with exams in June.
 | What is vitally important is that the fire authority takes its time to find out exactly what happened and provide some answers |
"We've got a few weeks to get ourselves sorted, but obviously the children are going to be very, very upset." Swansea Council cabinet member for education Mike Day said everybody at the school was devastated.
"The council is working closely with senior staff at the school to try and minimise the disruption for the pupils and local community.
The school had just been refurbished and the swimming pool reopened only last week. The leisure centre will remain shut until further notice and school outdoor pursuit trips to Rhossili planned for next week have been cancelled.
Plaid Cymru councillor Darren Price said: "There are so many questions being asked at the moment - locals really don't know what has happened.
"What is vitally important is that the fire authority takes its time to find out exactly what happened and provide some answers to what is currently a huge grey area."
Social Justice Minister Edwina Hart, the Gower AM, visited the school and promised to keep in touch with investigators trying to discover the cause.
Anyone with information can call police on 01792 456999 or Crimestoppers on 0800 555111.