The student, who was arrested yesterday, confessed that he had a great liking for Hollywood action thrillers, particularly that of Stallone, police said. Reading detective novels was also his chief hobby, sources told PTI.
The 15-year-old boy, who was staying with his father and stepmother, told police that he used to carry along with him a knife even while going to school.
The motive behind the murder of his classmate Lejin Varghese was to avenge a petty clash between the two when they were in the ninth standard, police said.
The school had opened for vacation class on Monday and after classes were over by 1130 am, the boy told police that he took his classmate to the bathroom, hit him many times and slit his throat with a knife and a piece of broken glass.
To ensure that Lejin did not survive the ordeal, he hit him with a granite piece several times, the boy told police.
The boy then went to a church and then to Ambalapuzha. He was arrested from the Changanassery railway station.
The relatives of slained Lejin, who hails from a poor family, began searching for him when he failed to return home. His body was found in the school compound on Monday.