Officials said the case which was investigated by the local police had been transferred to CB-CID.
The announcement was welcomed by the Dalits of Natham Colony, Annanagar and Kondampatti who burst crackers.
A total of 268 houses were torched, 54 vehicles destroyed, jewels and valuables looted in the violence unleashed on Nov 7 by the Caste Hindus after a man committed suicide over his daugther marrying a Dalit man of Natham Colony.
After the attack came to light, police arrested more than 90 people and National Commission for SC/ST officials and leaders of various political parties visited the colonies and condemned the violence targeting the Dalits.
District Collector R.Lilly, Salem Range DIG Sanjay Kumar, City Commissioner Mahali, Superintendents of Police Asra Garg (Dharmapuri), M.Ashokumar (Krishnagiri) camped in the affected areas and restored normalcy.
Two polce personnel, including an Inspector, had been suspended while the DSP of the area shifted to Salem Range office pending inquiry into alleged failure of police to prevent the attack.