Police are conducting forensic tests on a firearm found in the Highland town where a banker was shot dead on his own doorstep.
Workmen found the gun in a nearby drain
Northern Constabulary said it was too early to say whether the gun was linked to the murder of Nairn bank executive Alistair Wilson.
The 30-year-old was shot in the head at his home on the town's Crescent Road on the evening of Sunday, 28 November.
The Seafield Road area was closed off after the discovery on Wednesday.
Detectives were called to the scene after workmen found the gun in a drain near Nairn Old Parish Church.
The road is half a mile from where the shooting took place.
Mr Wilson's wife, Veronica, had opened the door to the killer, who asked for her husband by name.
Alistair Wilson, pictured on a family outing on the day he was murdered
After the shots were fired the gunman ran from Crescent Road towards the links area of Nairn.
Mr Wilson, the father of two young boys, was rushed to hospital where he died.
The gunman is described as being aged 35-40, stocky, clean shaven and wearing a baseball hat and blouson jacket.