New Delhi: An autopsy that suggests a Delhi Police sharpshooter was neither murdered with the revolver found at the spot nor shot from behind has raised a finger towards nexus between the police, builders and the underworld.

For starters the autopsy report of slain Assistant Commissioner of Police Rajbir Singh has raised several disturbing questions and punctured close friend Vijay Bharadwaj's admission that he killed Singh in cold blood.

In his statement to the police, Bharadwaj said he walked up behind Singh and fired three shots at point blank range with a 0.32 bore revolver, giving his victim no chance to react.

However, the autopsy reveals something quite different. Singh was neither killed with a 0.32 bore weapon nor from bullet shots from behind - thus contradicting the confessional statement of Bharadwaj.

"The autopsy report suggests that Singh was not fired at from the weapon seized from the crime scene. It is a gun of a different calibre," a well-placed police source said.

A team of doctors headed by S.K. Sharma and Ram Pal found that Singh died instantly after being hit by two bullets in the head.

"One of the bullets pierced right through his head and it was likely to have been fired from the front as the victim's forehead had a small clear-cut hole while the back had a large hole," Sharma said.

The police are also looking at the possibility of other people being present during the crime.

After the post-mortem examination, investigators have found many contradictions in Bhardwaj's confession. They now suspect there were more people in Bhardwaj's office and he could be taking the blame to save some influential people.

"We are interrogating him closely as there are distortions to the exact sequence of events that played out Monday evening," said a police official, who is part of the investigating team.