Top Maoist leader Narayan Sanyal passed away in a south Kolkata hospital late on Monday night. Sanyal, a Communist Party of India-Maoist (CPI-M) activist, aged 78 was suffering from cancer, reported The Hindustan Times.

Sanyal was among the last links between the CPI-Marxist-Leninist (ML) and its offshoot CPI(Maoist), described as India’s gravest internal security threat.

According to The Hindu, Sanyal was arrested in 2005 and considered the second most important leader of the outlawed CPI-M. He was born in Bogra district of undivided India, which is now in Bangladesh, to an affluent Bengali family. His father was a well-known Congress leader, district chief, who hosted leaders, among others, like Bidhan Chandra Roy, former Chief Minister of West Bengal and Congress leader Sarojini Naidu. The Sanyal family shifted to West Bengal in 1940s.

Before he joined the CPI(ML), Sanyal used to work in the United Bank of India in Kolkata. Post the split of CPI-ML by Satyanarayan Singh, Sanyal went to Bihar to work with peasants. “In 1968, top Naxal leaders Saroj Dutta and Sushital Roychowdhury (both became politburo members of the CPI(ML) when the party was formed in 1969) had several rounds of discussion with me, following which I left for Bihar to organise the movement there,” Sanyal had said.

In 1972-73, Sanyal was arrested and as part of a general amnesty granted to ML leaders, he was released in 1977. “Even when in jail, a group of us had been discussing how to avoid the mistakes that led to the setback in 1972 and how to reorganise the movement. We contacted old comrades soon after coming out of jail and starting working on an evaluation of the first phase (1967-72), based on which the movement will be rebuilt,” said Sanyal in an interview to The Hindustan Times.

Following his release, Sanyal returned to Bihar to work with CPI-ML-Party Unity. The Unity led a movement to resist the big landholders and gained momentum. Sanyal played a crucial role in the movement and was made the Secretary of Party Unity in 1987.

The 1990s saw the merger of various Naxalite groups. Sanyal was vital in the union of People’s War PWG and Maoist Communist Center MCC in 2004- a partnership which led to the formation of CPI-Maoist.

He was released in 2014 due to ailing health. Since then, he had been living in Kolkata.

Hindustan Times reports that Narayan Sanyal’s body would be kept at the mortuary for two days and last rights are scheduled to be performed on April 20.