By Jyotsna Singh
BBC News, Delhi
A top Delhi police official, Rajbir Singh, has been shot dead in a suburb near the Indian capital, police say.
The blast came after a lull in militant activities
Reports say a long-running dispute over property may have led to the killing. Police say a property dealer has been arrested in connection with the murder.
Mr Singh headed the special operation crime team of Delhi police.
He came to be known as an "encounter specialist" for his successful handling of several cases related to anti-terrorism operations.
The Gurgaon police Commissioner, Mohinder Lal, said Mr Singh was shot from point blank range with his own gun when he visited the office of a property dealer in Gurgaon late on Monday evening.
Police say the shooting followed after a heated argument between Mr Singh and the property dealer.
"The accused has surrendered and confessed to the crime. It appears that the dispute was over the profit both of them got in a property deal," Commissioner Mohinder Lal was reported as saying.
Rajbir Singh, 48, was involved in more than 50 shoot-outs with criminals and militants.
He was provided with high level personal security by the government because of a number of threats he faced from terrorist groups. But police say he only had one personal guard with him at the time of his killing.
Rajbir Singh joined Delhi police in 1982. Throughout his 25 year career, he had his share of glories and controversies.
He played an important part in solving several high-profile cases such as the attacks on the central parliament and the Red Fort in Delhi.
But he was transferred out of the special team following allegations of corruption - only to be reinstated later after he was cleared.
Questions have also been raised over his reported role in the killing of two alleged Pakistani militants in a shootout at a shopping mall in Delhi. Police claimed they were planning to attack the mall.