The incident took place in Kalkaji at around 9:30 pm. The victim has been identified as Gopal Negi.
He and owner of a neighbouring jewellery shop were at loggerheads over parking issue for quite a while.
Tonight, the property dealer allegedly spit in front of the jewellery shop following which there was an argument and a scuffle and he was hit from a bullet fired from a firearm of the jewellery shop's security guard.
A senior police official said it was not clear whether the security guard opened fire or somebody else snatched the gun and shot the property dealer.
The victim was rushed to a nearby hospital where he was declared brought dead.
The official said they are investigating the case.