A Class 11 student who allegedly wanted to postpone a parent-teacher meeting and exams has been arrested in connection with the killing of a seven-year-old boy in Gurgaon's Ryan's International School, the CBI said on Wednesday.
He has been sent to three-day CBI remand by Gurgaon court.
In a sensational twist to the case, the high school student, who is about 16 years old, was apprehended late on Tuesday night for allegedly killing his junior inside the school, said a CBI spokesperson.
Pradyuman, a Class 2 student of the school, was found dead with his throat slit by a sharp-edged weapon on the morning of September 8.
The CBI did not find any evidence against bus conductor Ashok Kumar, who was the Gurgaon Police's sole accused in the gruesome killing.
The murder weapon, a knife, was found in the commode of the toilet where the killing allegedly took place, said CBI spokesperson Abhishek Dayal.
It was the same knife seized by the Gurgaon Police, he said.
According to the agency, the Class 11 student, believed to be weak in his studies, allegedly slit Pradyuman's throat to get the school to declare a holiday in order to defer a scheduled parent-teacher meeting (PTM) and an examination.
The CBI was able to piece together elements of the crime by analysing the CCTV footage, scientific and forensic examination, analysis of the crime scene and by questioning students, teachers and staff of the school, an official said.
The CBI spokesperson said the minor student was apprehended last night at 11.30 pm in accordance with the provisions of the Juvenile Justice Act.
"His parents were kept in the loop and all measures in accordance with the JJ Act were complied with. He remains our prime suspect."
He said the agency analysed CCTV footage, which shows the movement of people in and out of the toilet, on the basis of which it narrowed the list of suspects.
The agency has not found any evidence of sexual assault, he said.
Based on CCTV footage and crime scene analysis, the agency examined all the suspects in the matter, sources said.
The mobile records of all the suspects were scrutinised and examined by the CBI special crime team.
Although the Class 11 student had planned a killing on September 8, the "child in conflict with law" had not identified his target, Dayal said.
It was a coincidence that Pradyuman reached the toilet and became a victim of the ghastly plan hatched by the senior student, sources said.
The investigation is still on.
The CBI's findings will be a major embarrassment for the Gurgaon Police, which had blamed Ashok Kumar and alleged that he was waiting in the toilet with a knife.
The police had formed 14 SIT teams.
Kumar, a resident of Ghamdoj village in Sohna, was hired by a school bus contractor around seven months before the killing.
Villagers in Ghamdoj had said Kumar had been framed and he had no previous history of being involved in any crime.
"Now that they have arrested this student, it has been proven that the doubt we had about the police investigation was right," Pradyuman's father Varun Thakur told the media.