Ashok Kumar, the bus conductor, arrested by Gurgaon Police for the murder of Pradyuman Thakur at Ryan International School, Gurgaon, is "not in the picture" as far as the seven-year-old boy's killing is concerned, sources in the Central Bureau of Investigation said today.

This development came soon after the CBI arrested a Class XI from the same school in the Pradyuman murder case.

The seven-year-old boy was found with his throat slit on the morning of September 8. Later the same day, Gurgaon Police arrested Ashok Kumar, a bus conductor at the school, saying he killed Pradyuman after attempting to sexually assault the boy.

That story seems to be unraveling now with the CBI saying the Class XI student, detained today, is the prime suspect in Pradyuman's killing. The student was held on the basis of CCTV footage and other scientific evidence, including call records, the CBI said.

Initial probe shows the Class XI student wanted school exams at a parent-teacher meeting at Ryan International School postponed, the CBI said. The murder was committed in order to get Ryan to declare a holiday, the CBI suggested.

The agency, however, added that it could not with certainty that Pradyuman was a "pre-planned target". Sources added that a day before Pradyuman's murder the detained minor is believed to have told other Ryan schoolchildren not to prepare for exams as there would be a holiday at school.

The detained Class XI student will be produced before a competent court for further proceedings, the CBI said.

Pradyuman murder: CBI trashes Gurgaon Police probe, says conductor not in picture

The CBI has said a Class XI student of Ryan International School is the prime suspect in seven-year-old Pradyuman Thakur's killing. Gurgaon Police had earlier arrested a bus conductor for the murder.