New Delhi: The CBI on Wednesday claimed that Pradyuman Thakur, the Gurgaon Class II student who was found with his throat slit in a school toilet early this September, was killed by a senior who wanted exams and a parent-teacher meeting to be postponed.

The 16-year-old accused, who studies in Class XI and cannot be named as he is a minor, was picked up on Tuesday night before being produced in a juvenile court, which remanded him in CBI custody for three days.

The father of the detained student accused the CBI of framing his son. "My son has not committed the crime," he said.

A CBI official said the teen was under psychiatric treatment for nearly a year for anger management. (See Page 4)

Earlier, Haryana police had arrested a school bus conductor for the September 8 murder at Ryan International School. The police had said the conductor, Ashok Kumar, had confessed to killing Pradyuman after the seven-year-old resisted his sexual advances.

On Wednesday, the CBI said Ashok had no role in the murder. "But we are still investigating his role in the destruction of evidence among others," CBI spokesperson Abhishek Dayal said.

The Haryana government had transferred the case to the central agency following pressure from the parents.

Dayal said the agency "apprehended the student" after a "thorough investigation".

Sources in the CBI said the accused was the first who had noticed Pradyuman after the attack and alerted the school's staff and teachers. A close scan of a previously ignored CCTV footage showed the teen chaperoning Pradyuman in the toilet. "The accused student changed his statements several times and later broke down and confessed," a CBI official claimed.

CBI sources said they had reviewed the suspect's school records and found he was very weak in studies. They said the school exam was scheduled three days after Pradyuman's murder, and the parent-teacher meeting two days later.