This announcement came after the father of the 27-year-old Deputy Superintendent of Police, Vishnupriya, who lived in Tamil Nadu's Namakkal district, and another police officer demanded a CBI enquiry.
Her father Ravi said, "I believe truth would come out only if there's a CBI enquiry."
Maheswari, a Deputy Superintendent of Police and a friend of Vishnupriya said, "Senior officers threatened to issue memo to her if she did not arrest Yuvaraj the key accused in the Gokulraj death case."
Police however denied that there was any foul play.
Vishnupriya was investigating a case involving the death of a young Dalit man Gokularaj, who was found dead on a railway track in June this year. CCTV images at a temple showed him being dragged by a group of people, while he was talking to an upper caste young woman.
The same day Gokulraj's body was found on a railway track. Though the police have arrested several people belonging to a caste group suspected to be behind the attack, their leader, Yuvaraj, is still at large.
In her suicide note, Vishnupriya had called herself "not fit" and "not suitable" for the job and asks not to "relate my death to the case".
The Chief of Crime Branch of the CID Mr Mahesh Kumar Aggarwal confirmed that the department would take over the case.
This is the second officer in Tamil Nadu to have committed suicide in eight months. In February, an agricultural engineer Muthukumarasamy killed himself reportedly under pressure from the Agriculture Minister Agri Krishnamoorthy who was sacked, arrested and is out now on bail.
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