A fourth person has been charged in connection with a homicide investigation in Smiths Falls.
Ontario Provincial Police say 42-year-old Mark Fenton of Smiths Falls was arrested April 21, 2026, and charged with accessory after the fact to murder. He remains in custody and is scheduled to appear in court in Perth on April 22.
The charge is tied to the death of Robbie Thomson, who was reported missing in October 2023 and is believed to have disappeared between October 12 and 18 of that year.
In October 2025, three individuals were arrested and charged with first-degree murder. A day later, police executed a search warrant at a property on Kelly Jordan Road in Montague Township, where human remains were located and later identified as Thomson.
Police say they will maintain a presence at the property as the investigation continues.
The Lanark County OPP, working with the Smiths Falls Police Service and under the direction of the OPP Criminal Investigation Branch, continue to investigate with support from the Office of the Chief Coroner and the Ontario Forensic Pathology Service.
Anyone with information is asked to contact the Lanark County OPP or Crime Stoppers.
