He is said to have gone missing after a press meet on the Thoothukudi firing
Human Rights Defenders Alert - India (HRDA), an organisation that works to defend human rights activists facing threats, has appealed to the Chennai Police Commissioner to take immediate steps to trace environmental activist R.S. Mugilan, who is said to have been missing since Friday.

Mr. Mugilan went missing during a train journey from Chennai to Madurai after addressing the media in Chennai regarding the police firing in Thoothukudi during the protests against Sterlite Copper last May, the HRDA said.