New Delhi/IBNS: The Central Bureau of Investigation (CBI) has taken over the case of the death of a 20-year-old veterinary student, whose body was found in a college hostel in Kerala's Wayanad district.

The body of the student, Sidharthan JS, was found inside the hostel's bathroom on February 18.

His family had alleged he was subjected to ragging by other students, including activists of the Students' Federation of India (SFI), the student wing of the Communist Party of India (Marxist), or CPI(M).

Sidharthan was "continuously" assaulted for 29 hours by seniors and classmates before he died by suicide, the Kerala Police said in the suicide abetment case file they gave to the CBI, The Indian Express reported.

Sub-inspector Prashobh PV of Vythiri police station wrote that seniors and peers "physically and mentally tortured" Sidharthan, driving him to die by suicide, according to The Indian Express report.

"... They assaulted Sidharthan on February 16 from 9 am to 2 pm till February 17 continuously with hand and using a belt and subjected him to cruel ragging. This made him in an utter stage of mental stress and feeling that he can neither continue study in the Institute and complete this course nor go home dropping the course.

"As he is so mentally stressed, he felt that there is no option for him other than suicide, he committed suicide by hanging himself in the bathroom of men's hostel in between 12.30 pm and 13.45 pm on February 18," the police report said, according to The Indian Express story.

The CBI had re-registered the first information report (FIR) filed with Wayanad's Vythiri police station against 20 people on Friday night, within hours of getting a notification from the Centre.

The procedure in state-referred cases is such that the CBI starts an investigation by re-registering the FIR.

Kerala Chief Minister Pinarayi Vijayan had assured a CBI probe on March 9 after a political uproar over the case.

The issue snowballed into a huge controversy after the opposition Congress and the BJP alleged that the state government was yet to hand over key files to the CBI weeks after the assurance.