Himanshu Roy, a senior Mumbai police officer involved in many high-profile investigations, committed suicide at his home on Friday.
Himanshu Roy was an Additional Director General of Police. He had earlier headed the Anti-Terror Squad of Maharashtra.
He was believed to be battling cancer and had gone on a long leave on medical grounds.
The 1988 batch Indian Police Service (IPS) Officer allegedly shot himself using his service revolver at his home in Mumbai around 1.40 pm. He was brought dead to hospital.
Himanshu Roy led investigations into several big cases including the 2013 Indian Premier League spot-fixing, the murder of Pallavi Purkayastha and the J Dey murder.
While he was heading the anti-terror squad, he arrested software engineer Anees Ansari for allegedly planning to blow up the American School.
"He was a very bright officer. Such a tragedy," said MN Singh, who was his superior at a point.
The officer, regarded by colleagues as committed, sharp and popular, had seven years of service left.
Sarup Patnaik, one of his colleagues, said: "He was a fitness freak. He was at an advanced stage of cancer and couldn't take it anymore. It is very, very unfortunate."
In 2015, Himanshu Roy was among police officers who were seen to be sidelined after they wrote to the Maharashtra home department alleging poor treatment by seniors and favouritism in transfers. That was the time he was removed as chief of the anti-terror squad - an elite posting - and was appointed additional director general in charge of police housing.