Scott Snowden was jailed for 33 years in July 2013 for masterminding the murder of Thomas Sharkey, his son Thomas junior, and eight-year-old daughter Bridget in a fire at their home in Scott Court, Helensburgh, on July 24, 2011.

Co-accused Robert Jennings – who set the fire by pouring petrol through the letter box on the instructions of Snowden – was jailed for 29 years.

Last week, a fire erupted in the early hours of Friday, April 11 at the property on Old Luss Road.

Two fire engines from Helensburgh Fire Station attended a ‘small fire’ at about 12.45am and the flames were extinguished using two hose reel jets.

The front door and steps leading up to the property appeared scorched in the hours following the incident.

Emergency crews said no one was injured in the incident, which is being treated as wilful fireraising by police.

Chief Inspector Gary Stitt said the investigation is still in the ‘early stages’.

He said: “We are treating this as a deliberate act. There is no information to suggested it was target against any one individual.

“It was a minor fire and the investigation is in the early stages.” Although Chief Inspector Stitt would not confirm or deny the owner of the property, he did reiterate there is a heightened sensitivity to fires in Helensburgh due to past incidents.

He added: “We would ask anyone who saw anything to get in touch with police on 101.” Calls can also be made to Crimestoppers anonymously on 0800 555 111.

In March, Snowden and Jennings launched a bid for freedom with Snowden set to appeal his conviction and Jennings to appeal his convictions and sentence. The procedural appeal hearing, which takes place in front of a single judge, has been fixed for April 30 at the High Court in Edinburgh.