"In every school in Delhi, rigorous police verification should be done of every staff, every person who enters the school premises within three weeks," Delhi's Deputy Chief Minister Manish Sisodia said on Monday.

A large number of policemen were stationed at the school a day after violence erupted during a protest by parents and local residents. Protesters set fire to a liquor shop in the neighbourhood, prompting the police to use lathis or batons to control the mob. A police officer was suspended today for using force against journalists covering the protest.

Ryan Pinto, CEO of Ryan International Schools Group, and his parents filed an anticipatory bail plea in the Bombay High Court. Investigators have travelled to Mumbai, where the school is headquartered, to question the management.

The school will stay shut for now except for students of Classes 6 to 12, who will sit for exams from Wednesday. The police claimed that evidence from the scene of crime

had been tampered, news agency PTI said.

More teachers and staff are being questioned at the school today. The principal, Neerja Batra, was detained and questioned till after midnight yesterday. A team of Haryana police is headed for Mumbai to question the school's management.

The body of the 7-year-old, a student of Class 2, was found inside the school's toilet on Friday less than an hour after his father had dropped him off. His throat had been slit.

The police have arrested the conductor of his school bus, Ashok. They say he confessed that he tried to sexually assault Pradyuman and killed him when he resisted.

A report by a three-member Special Investigation Team has said many of the CCTV cameras installed in the school campus were not working. The team also found that there were no separate toilets for school bus conductors and drivers, which meant they went to the same toilet used by students. The school also hired staff without proper background checks and police verification, the report said.

Haryana's Education Minister Ram Bilas Sharma has said that the state government is not against the idea of a CBI probe.