Stan Swamy is accused of instigating the Bhima Koregaon violence.
A special NIA court today rejected the bail plea of Stan Swamy, the tribal rights activist and Jesuit priest arrested earlier this month for his alleged involvement in the 2018 Bhima Koregaon violence in Maharashtra.
The 83-year-old, who is under judicial custody, had sought bail on health grounds. He is now lodged in the quarantine ward at Taloja Jail, near Mumbai.
Mr Swamy was picked up from his home in Ranchi, Jharkhand, by a team of NIA officials from Delhi. His arrest had sparked an outrage across the country, evoking criticism from several circles.
"It (the NDA government) crossed all limits today when someone like Stan Swamy was arrested. He is someone who has been working in Jharkhand for years, in the remote faraway villages, wandering in the jungles, just so that the adivasis, Dalits, and minority populations here could be reached," Jharkhand Chief Minister Hemant Soren had said.
Others who dubbed the arrest an attack on civil liberties include CPI(M) General Secretary Sitaram Yechury, Kerala Chief Minister Pinarayi Vijayan, and DMK leader Kanimozhi.
The cleric was the 16th person to be arrested in the Bhima Koregaon violence case, in which people have been booked under various sections of the Indian Penal Code and the anti-terror law UAPA.
Violence had erupted in the vicinity of a war memorial in Bhima Koregaon village near Pune on January 1, 2018, allegedly after provocative speeches were made during the Elgar Parishad conclave held a day earlier at Shaniwarwada in Pune city.
NIA investigations reportedly established that Stan Swamy was actively involved in the activities of the CPI (Maoist), and had a role in instigating the violence.
The NIA has now filed a supplementary charge sheet against Mr Swamy and other activists.