The case was earlier being probed by the Kotturpuram police of Chennai.
The CBI has taken over the investigation in the case involving the death of Indian Institute of Technology-Madras (IIT-M) student who was found dead at her hostel room last month, officials said on Monday.
The Special Crime Branch of the agency's Chennai unit re-registered the first information reporter of the local police on December 27 and took over the investigation in the matter.
The body of the IIT student was found hanging from a fan in her hostel room on November 9, officials said.
The case was earlier being probed by the Kotturpuram police of Chennai and later transferred to the CCB.
The investigation was transferred to the Central Bureau of Investigation (CBI) when her parents, along with a delegation of Kerala MPs, met Prime Minister Narendra Modi and Union Home Minister Amit Shah here on December 5 and sought justice for their daughter.
Her family had found her suicide notes on her mobile phone.
Immediately after her death, her father had alleged in Chennai that he had evidence to prove that the student was being harassed by some professors in the department of humanities and social sciences.
He wanted a fair probe as he was concerned that her phone might be tampered with.