A prominent Indian scholar accused of instigating caste clashes has turned himself into federal investigators.
Police accuse Anand Teltumbde of instigating violence at Bhima Koregaon village in Maharashtra state in 2018.
Prof Teltumbde has said the charges are fabricated.
The violence broke out at the 200th anniversary celebration of a battle where Dalits (formerly untouchables) fought alongside British colonial forces to defeat an upper-caste ruler.
Stones were thrown at those who had gathered at the event, resulting in the death of one person.
Clashes then broke out across the state and in other parts of the country.
During investigations into the incident, police blamed several activists and academics including Prof Teltumbde, who is also a Dalit.
They said that his organisation, Elgar Parishad, was responsible for the violence which erupted in Bhima Koregaon.
He was charged under the Unlawful Activities and (Prevention) Act (UAPA), a controversial law that makes it difficult for the accused to get bail. Police raided his house last year in connection with the case.
Police also said that he was involved in a plot to assassinate Prime Minister Narendra Modi.
On 8 April, India's Supreme Court directed Prof Teltumbde and rights activist Gautam Navlakha to surrender to investigators within a week.
The two men had sought more time from the court, saying going to prison during the coronavirus pandemic was "virtually a death sentence". The top court rejected the plea.
"I am implicated on the basis of the five letters among 13 that the police purportedly recovered from the computers of two arrestees in the case," he wrote in a three-page letter a day before surrendering.
Prof Teltumbde is an engineer and Indian Institute of Management graduate, a top-rated graduate school in India. He also used to teach at IIT, Kharagpur.
He has a doctorate in cybernetics and heads the big data analytics programme for the Goa institute of Management.