Intruder slashes pupils' trousers
Police believe the latest incidents in Oxfordshire are linked to 13 others in schools throughout five south Midlands counties.
They believe one man is responsible for all the damage. They say he could have easy access to the schools, possibly as a delivery man.
The latest attack happened at Wood Green comprehensive school in Witney, Oxfordshire, on July 13, when three pairs of boys' trousers were shredded.
The intruder was caught on the school's security cameras during the daytime attak. He is in his 30s, about 6ft tall, and wore a casual top with patched shoulders.
Two days earlier four pairs of jeans were ripped in changing rooms at Marlborough School, Woodstock, near Oxford.
Most of the incidents occurred between 1995 and 1998. They were all at secondary schools, apart from one incident at a leisure centre attached to a school.
The incidents halted after police released a photofit image of the suspect in April 1998.
The two attacks this month were the first reported since then.
Detective Sergeant Simon Morton, of Thames Valley Police, who is heading the inquiry, said: "It really is bizarre."