The student - whose name and face were not revealed on television - said he had been a target of bullying schoolmates.

He said the most serious incident took place in January 2001, when he was beaten by about five students for two minutes. He was taken to a hospital and police were called.

He said the police later told him that his attackers had been warned, and advised him not to pursue the case because it was exam time.

He said his teacher told his mother that he was injured while playing with his schoolmates.

'A major incident was turned into a situation as if nothing had happened and just covered up.'

Police yesterday identified several students who might be involved in the videotaped incident. Some may have graduated.

They will be interviewed at a later date as officers try to determine if the case involved criminal behaviour. Teachers met parents last night to discuss the situation. The school launched an internal probe after the video clip surfaced last month, but it claimed the student later told teachers that the incident was play rather than a real attack. Mak Oi-ying, the principal of CMA Secondary School, yesterday declined to comment on the accusations from the former student.

The police and the Education and Manpower Bureau last night said they would look into the case.

Secretary for Education and Manpower Arthur Li Kwok-cheung said officials would ask all schools to check if there were any unreported bullying cases.

In the past academic year, 1,042 cases of bullying and 566 incidents of violence were reported in primary and secondary schools.