By Sanjeev Miglani

A top U.N. human rights official has deplored the death in custody of an 84-year-old Indian Christian priest who campaigned for the rights of tribal people and was detained under an anti-terrorism law and denied bail.

Father Stan Swamy was arrested last year on suspicion of ties to a banned radical leftist group that police accused of instigating violence in Maharashtra state in 2018.

Swamy, who suffered from Parkinson's and also contracted COVID-19 while in prison, died in a Mumbai hospital on Monday.

"The news from India today is devastating. Human Rights Defender & Jesuit priest Fr Stan Swamy has died in custody, nine months after his arrest on false charges of terrorism," U.N. special rapporteur for human rights defenders, Mary Lawlor, said on Twitter.

"Jailing HRDs is inexcusable," she added, referring to human rights defenders.

The National Investigation Agency, which was pursuing the case against Swamy, did not respond to requests for comment. The federal home ministry and the foreign ministry also did not respond to a request for comment.

The government has previously in court hearings denied accusations of mistreatment of Swamy and said the law must be allowed to take its course.

Supporters of Prime Minister Narendra Modi's ruling Bharatiya Janata Party said there could be no tolerance of violence by Maoist guerrillas, some of whom operate in remote areas where tribal people live.

Swamy was the oldest of a dozen people, most of them academics and human rights activists, accused of violence in 2018 and imprisoned under the Unlawful Activities Prevention Act, which allows for prolonged detention for questioning.

His death will revive criticism of the increasing use of the antiterrorism law under Modi's government. Opponents of the law say it is used to unfairly hound people critical of the government.

Eamon Gilmore, the EU's special representative for human rights, said on Twitter he was very saddened by the death of the defender of the rights of indigenous people.

"The EU had been raising his case repeatedly with authorities," he said.

Swamy, who denied any links to any outlawed group, had repeatedly asked for bail, recently telling the court in a video conference his health had deteriorated in prison and that he would soon die.

He said he had difficulty eating and drinking because of his Parkinson's and had asked the court to allow him use of a straw and a sipper. The court agreed to the request after nearly three weeks.

A leader of the main opposition Congress party, Jairam Ramesh, criticised the government for the death of "such a passionate crusader for social justice".

"Who in the apparatus of the Indian state will be held responsible for this tragedy? Make no mistake — it is the Indian state that killed Fr. Stan Swamy," Ramesh said.