MK Stalin said the incident is a "black mark" in Tamil Nadu's history.
A Deputy Superintendent of Police and three constables charged by an inquiry commission with unprovoked firing against the anti-Sterlite protesters in 2018 in Thoothukudi, were placed under suspension by Tamil Nadu Director General of Police (DGP) C Sylendra Babu on Friday.
The Justice Aruna Jagadeesan Commission of Inquiry, which probed the Thoothukudi police firing that claimed 13 lives, faulted the police for indulging in excess and recommended appropriate action against the police officials and others.
The inquiry commission's report tabled in the Assembly on Tuesday said the police shooting on the protesters was unprovoked.
On Wednesday, Chief Minister M K Stalin assured the Assembly that those responsible for the "blood-chilling" police firing in Thoothukudi during the previous AIADMK regime, will be punished.
Appropriate disciplinary action has also been initiated against the then police officials including the IGP of the south zone, DIG of Tirunelveli, the superintendent of police, Thoothukudi, a DSP, three inspectors, a sub-inspector and seven constables, he said.
Describing the incident as a "black mark" in Tamil Nadu's history that none could forget or cover-up, Mr Stalin had said departmental action is being taken on the then collector while disciplinary action has been initiated on three revenue officials.
"The guilty will be brought to book and punished," Mr Stalin said and remarked that the firing incident was proof of how a government should not conduct itself.
The inquiry report had recommended action against 17 police officials, then district collector, and three revenue officials.
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