My friend Kanwar Pal Singh Gill, who has died aged 82, was a controversial police chief in India, credited with bringing the Punjab insurgency under control in the early 1990s – his admirers called him India’s Top Cop – but criticised for alleged human rights violations.

He was born in Ludhiana, Punjab, but after independence was brought up in Simla (now Shimla) in the Himalayan foothills. His father, Rachpal Singh Gill, was a high-ranking government engineer. His mother, Amrit Kaur, a homemaker, died when he was a schoolboy. His father then married a young doctor, Satwant Kaur.

I was at school with Gill at St Edward’s in Simla, a strict Catholic establishment. He was an above average scholar but was a withdrawn boy, possibly because of the grief of losing his mother.

After a degree in English from Punjab University, he qualified for the Indian police service and was posted in Assam. This was at a time of nationalism in Assam, when Bengalis were being attacked, regarded as foreigners and exploiters. Gill carried out his policing with a no-nonsense approach. He was once accused of kicking a lawbreaker to death.

Meanwhile the situation in Punjab, Gill’s home state, had become explosive. An organised group of Sikhs led by the preacher Bhindranwale was demanding an independent Sikh state. When Bhindranwale and his followers took over the Golden Temple in Amritsar in 1984, the prime minister, Indira Gandhi, ordered the army to storm the temple. Many, among them Bhindranwale, were killed. Mrs Gandhi was assassinated by her Sikh bodyguards; Sikhs living in Delhi were massacred by Hindus and the Hindus of Punjab were in turn massacred by Sikh separatists.

The government, working on the principle that only a Sikh could control the turbulent Sikhs, transferred Gill to Punjab. Hundreds of young Sikh militants were killed by the police. Leading Sikhs such as the writer Khushwant Singh questioned Gill’s methods. I in distant London could hardly believe what I was reading about my old school friend.

Outside his life in the police, he was a cultivated man. He wrote poetry in English and Urdu. But in 1996, following an incident at a party, he was found guilty of sexual harassment. He was fined and placed on parole.

When he retired from the police in 1995, he founded the Institute of Conflict Management in New Delhi, and wrote and edited books on the global threat of terrorism. He wrote and spoke about the Indian government’s lack of will in dealing with internal terrorism. He was nevertheless allotted a huge property by the government in the heart of the capital with high walls and armed guards. There were attempts on his life.

Groups of his opponents living in the UK persuaded the British authorities to prevent him from attending the 2012 London Olympics on the grounds that he was responsible for the deaths of innocent Sikhs in Punjab.

He is survived by his stepmother, his wife, Heminder, a daughter, Chitvan, and a son, Hemant.