Ruling out the angle of sexual assault, the CBI further said that the 16-year-old student used a knife as the murder weapon and later flushed it in the washroom.
Sources further told Zee Media that the senior student had a history of bad behaviour and was seen with a knife inside school campus on the day of the murder.
The detained student is suspected of having watched a pornographic clip in the morning, and on seeing Pradhuman Thakur in the school bathroom, he might have tried to sexually assault him when he entered it, minutes after he was dropped by his father, reported IANS.
The arrested minor reportedly told two classmates, not to worry about upcoming exams as he'll do something to 'handle' it. Furthermore, he had planned to hurt a student but did not specifically target Pradyuman.
"They (CBI) arrested my son last night. My son has not committed the crime. He informed gardener and teachers," said the father of the arrested student, further alleging that the CBI tried to force them to sign the confession documents.
"There was no spot of blood on my child's clothes. He was giving the exam," said the father. The 16-year-old was reportedly the first person to inform about Pradyuman's body in the bathroom.
The arrested minor will now be produced before the Juvenile Justice Board on Wednesday afternoon.
The police is yet to give a clean chit to school bus conductor Ashok Kumar, who was earlier arrested in connection with the case.
"The truth must prevail," Pradyuman's uncle told Zee Media on Wednesday.
On September 8, Class II student Pradyuman was found dead under mysterious circumstances inside the toilet of the school, his throat slit.