Stan Swamy, 83, is the olden person to be in custody in the Koregaon-Bhima case.
An 83-year-old Jesuit priest has been arrested by the National Investigation Agency (NIA) in connection with the probe into the 2018 violence in Maharashtra's Koregaon-Bhima village.
Father Stan Swamy, an activist working with tribals, was picked up from his home in Jharkhand capital Ranchi by a team of NIA officials from Delhi. The officials reportedly spent around 20 minutes at his home before taking him away.
The arrest has sparked outrage. Author and historian Ramachandra Guha said Stan Swamy has spent a "lifetime fighting for the rights of adivasis."
"That is why the Modi regime seeks to suppress and silence them; because for this regime, the profits of mining companies take precedence over the lives and livelihoods of adivasis," Mr Guha tweeted.
Lawyer-activist Prashant Bhushan tweeted, "...Now arrested by the NIA under UAPA! The venality of this BJP govt & NIA knows no bounds (sic)."
The probe agency claimed that Stan Swamy is a member of the banned Communist Party of India-Maoist (CPI-Maoist) and was "actively involved in its activities".
"He also received funds through an associate for furtherance of the CPI (Maoist) activities," officials of the probe agency said.
The agency said documents and propaganda material of the CPI (Maoist) and literature were seized from Stan Swamy, adding that he was in contact with the other accused in the Koregaon-Bhima case.
"The NIA is after me. I'm being pressurised to go to Bombay... The NIA questioned me for 15 hours... I'm being called to the Mumbai office of the NIA. I refuse to go there. I am 83 and have health issues. I don't want to expose myself to the coronavirus. I have never been to Bhima Koregaon," Stan Swamy had said in a video on October 6.
"If NIA wants to question me, they can do so via video-conferencing," he said.
Several prominent activists, scholars and lawyers have been jailed for over two years while they await trial.
Stan Swamy, who has several health issues, is the oldest person to be in custody in the Koregaon-Bhima case. He has been questioned several times in the past in connection with the case. Originally from Kerala, Stan Swamy has been working for tribals in Jharkhand for over five decades.
The case relates to an event on December 31, 2017 in Pune which was followed by violence and arson in Maharashtra that left one person dead.
Investigators claim that the activists at the Elgar Parishad meet had made inflammatory speeches and provocative statements, which it said had triggered violence the next day.
Last month, the Supreme Court declined to entertain a plea for an interim bail on medical grounds by lawyer-activist Sudha Bharadwaj, who is among the accused in the case. Ms Bharadwaj, 58, has been in jail in Mumbai for over two years and is suffering from diabetes and comorbidities and wanted interim bail so that she could take a medical check-up, her lawyer had said.
The investigation also claimed to have uncovered a plot to assassinate Prime Minister Narendra Modi.
During the investigation, the NIA said, it was revealed that senior leaders of the CPI (Maoist), a banned organisation under the Unlawful Activities (Prevention) Act, were in contact with the organisers of the Elgar Parishad event as well as the accused arrested in the case to spread Maoist and Naxal ideology and encourage unlawful activities.