For almost a decade Rajbir Singh had a licence to kill as head of a police special operations squad that hunted down India's worst criminals and terrorists. With 56 “encounters” — or kills — to his name, Delhi's assistant commissioner of police had earned five gallantry awards and plaudits from politicians.

His reign as the country's top cop came to a bloody end on Monday, when he was shot dead at close range in a property dealer's office in Gurgaon, an upmarket satellite town of Delhi.

The killing is the latest scandal to rock Gurgaon — home to many multinational companies and expatriate Indians — after the exposure of a kidney-selling racket there in January. It also raises questions about the alleged links between India's “encounter specialists” and criminal gangs or businessmen, especially in the booming property sector.

Vijay Bhardwaj, a property dealer who had been friends with Mr Singh for 21 years, has publicly confessed to shooting him after a dispute over money relating to a property deal. Mr Bhardwaj telephoned police and reporters to declare that he had acted in self-defence because he owed Mr Singh 9.5 million rupees (£120,000) and the police officer had threatened to kill him.

“ACP Rajbir Singh and I had dealings in property and we had a dispute over it,” he told a camera crew at the scene. “Today was the payment day and I could not put the money together. He said he would kill me.”

He added that he used a .32 calibre pistol that Mr Singh had given him as a present three days earlier. Police have arrested Mr Bhardwaj and say that they have no reason to doubt his testimony: that he shot Mr Singh on the spur of the moment, hitting him twice in the head. “He fired two shots and Mr Singh died on the spot. It was unplanned, all of a sudden,” Anil Dhawan, deputy police commissioner for Gurgaon, said. “There is no evidence that anyone else was involved.”

However, on Tuesday a man claiming to be a notorious gangster telephoned a TV channel and claimed that he was behind the murder. Prem Prakash “Bunty” Pandey, who is thought to operate from Vietnam, said that he sent two henchmen to kill Mr Singh because the officer was leading an operation to track him down.

Critics said that Mr Singh was a typical example of the police's “encounter specialists”, who often work for criminal gangs or kill unarmed suspects in fake shootouts to garner promotions and financial rewards.

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