A West Kilbride author and historian believes he has solved the 105 year old murder mystery at Portencross.
Since 1913, when Mary Gunn, pictured, was killed at the isolated Northbank Cottage, there has been books, newspaper articles, tv and radio programmes, which have examined the circumstances behind the shooting.
Sadly, the original police files into the murder have been lost over time, but Stephen Brown, who has carried out diligent archive research from newspapers of the period, believes he has uncovered the killer, and is writing a novel which will reveal his or her identity to coincide with the anniversary of the murder.

Largs and Millport Weekly News:
The investigation of the murder of Miss Gunn, who was a telephone operator, stretched as far as Canada, and sparked considerable interest.
Speaking to the 'News', Stephen Brown said: "One of the reasons that the horror of the Portencross Murder endures in the public imagination to this day is the notion that we too might be sitting in our living room on a peaceful Saturday evening when bullets come raining through our window, shot by an unknown assailant for no known reason.
"Yet this is what happened to Alexander McLaren, his wife Jessie, and her younger sister Mary Gunn.
"The unfortunate Mary died instantly from a shot to the heart, while the other two occupants of that tiny room were wounded.
"The murderer or motive was never discovered until now."
Indeed, Inspector Grant of Largs was the District Inspector of the County Constabulary and leading the investigation, when the call came through that there had been a fatal shooting. 
Quickly he gathered some men and made his way to the scene.
The nearest phone to the murder scene was at a nearby farm, as Alexander McLaren had to go on foot to raise the alarm. Ironically, even the police station didn't have a phone, and had to be summoned by a knock on the door by a neighbour. A doctor was also assigned to the scene. A number of bootprints were found at the location and examined, but the weapon was never found.
Mr Brown said: "My interest in the case started in the 1970s when my father who had grown up in Portencross told me the grisly details.
"It has resurfaced when a revolver had been found at Portencross and handed in to to police. 
"Whilst the lab were analysing the gun, the case was re-opened and my father and his mother were interviewed to see if they could shed any light on the case or the tenant of the grounds where the gun has been found.
"The gun turned out to be a World War 2 revolver and therefore too modern to be the murder weapon."
"Inspector Grant and his team from Largs were to remain at the scene for the entire week following the murder. They would investigate every lead, follow up every suggestion made by the public, no matter how daft, but the assassin was to elude them.
"A week after the murder a strong line of enquiry developed, and Grant moved to Glasgow where he was to interview a suspect.
"In West Kilbride the local police rashly announced that an arrest was imminent and crowds gathered outside the station to witness the comings and goings.
"In the end, the suspect had an alibi and the trail went cold. No further suspects were ever found or declared in the papers.
"I believe the local police were inadvertently lead by Alexander McLaren to look for a specific individual, and by the time they arrived at this conclusion, the real murderer had hidden almost every piece of evidence linking them to the crime."

Largs and Millport Weekly News:
The mystery sparked investigations even as far as Canada as Miss Gunn had previously headed across the Atlantic and to live with another sister and brother in law and lived there for a number of years, and police investigations wondered if a spurned lover could have been to blame. However, the author has ruled this out.
The new book 'Who Killed Mary Gunn?" comes out on 18 October to coincide with the 105th anniversary of the murder, and will be available to buy on Amazon, and will be published by the Transparent Publishing Company.