Mr. Sharavan Kumar has given valuable advice. Kindly follow it.
The RTI shall help to set the ball rolling.
In a similar case the complainant sent a telegramme to Chief Justice of the High Court and concerned Commissioner Police, SHO had to appear and were fined Rs.10000/
As per directives of apex court each state had to set up POLICE COMPLAINTS AUTHORITIES.
The state of Tamilnadu was late and then adhered to it.
The list of POLICE COMPLAINTS AUTHORITIES can be seen at Page 101 at:
https://www.humanrightsinitiative.org/publications/police/PoliceComplaintsAuthorities_ReformResisted.pdf
The state of TamilNadu does not feature here.
As per publication at following link: four-member committee will be headed by retired Judge of Madras High Court P. Shanmugham
https://www.thehindu.com/todays-paper/tp-national/tp-tamilnadu/police-complaints-authority-constituted/article1104671.ece
The authority will inquire into allegations of………………………………….involving serious abuse of authority by police personnel.
It has to submit its findings within 60 days of the receipt of the complaint. The four-member committee will be headed by retired Judge of Madras High Court P. Shanmugham, a release from the Home Minister's Office said.
There are other publications at:
https://articles.timesofindia.indiatimes.com/2013-09-14/chennai/42061785_1_state-human-rights-commission-police-reforms-minimum-tenure
https://www.humanrightsinitiative.org/programs/aj/police/india/initiatives/state_compliance_analysis/tamilnadu_chri_compliance_analysis.pdf
https://www.humanrightsinitiative.org/programs/aj/police/india/initiatives/state_compliance_analysis/tamilnadu_chri_compliance_analysis.pdf
Tamil Nadu Government Compliance with Supreme Court Directives on Police Reform
6. Police Complaints Authorities
There is another thread on POLICE COMPLAINTS AUTHORITIES at:
https://www.lawyersclubindia.com/forum/Contact-details-92278.asp#.Uod7G9KAqWM
Kindly update the address of Tamilnadu POLICE COMPLAINTS AUTHORITIE if you get it.