Vandals have caused £50,000 of damage at an East Yorkshire school by smashing computers, smearing excrement on walls and desks and writing obscene graffiti.
Shocked police found that every computer and TV screen at Bridlington School Sports College in Bessingby Road had been destroyed in the attack.
The attackers also smashed windows and doors after entering the school between Friday night and Monday morning.
Police want to trace three people seen on CCTV in the area on Saturday night.
A Humberside Police spokesman said: "This is one of the worst crimes of its type I have seen for several years.
"It is a very nasty anti-social crime which will affect a large number of people and cost a huge amount of money to put right.
"We appeal for witnesses to come forward at the earliest opportunity."