A lawyer accused of involvement in the protests against Sterlite Copper’s now closed smelter in Tamil Nadu’s Thoothukudi district last month was arrested on Wednesday night at the Chennai airport, ANI reported.

Thirteen people agitating against the expansion of the smelter were killed in police firing on May 22 and May 23 – prompting the state government to permanently shut down the plant days later. Several people were arrested for rioting, burning vehicles on the collectorate campus, stone pelting and damaging public property.

The Madurai bench of the Madras High Court had on Monday dismissed S Vanchinathan’s petition for anticipatory bail. Another advocate, K Hariragavan, booked with Vanchinathan, was also denied anticipatory bail.

The advocates had said they had not indulged in violence during the protests and that they were present at the spot only to provide legal assistance to protestors, according to The New Indian Express. The state government, however, accused them of violating prohibitory orders and instigating protestors. The government claimed that the police had taken action only after a mob destroyed 200 vehicles and nearly 72 policemen were injured.

The court said the advocates should not shy away from a police inquiry. It said they had taken a lead role in organising the protests, though they cannot be blamed for the violence.

Police had earlier booked the two advocates under various sections of the Indian Penal Code for rioting, assault of public servants, criminal intimidation, and under the Tamil Nadu Public Property (Prevention of Damage and Loss) Act, 1992.

For more than two decades, activists in Thoothukudi have accused Sterlite of contaminating the region’s air and water resources, and causing breathing disorders, skin diseases, heart conditions and cancer. Since February, there were large-scale protests against the company’s copper smelter, which had the capacity to produce 4.38 lakh tonnes of anodes per annum, or 1,200 tonnes per day.