Ontario Provincial Police (OPP) announced that two additional people have been arrested in connection to the death of a Clarence-Rockland man.
Robert Prevost, 63, was last seen at his home on Laurier Street in Clarence-Rockland in early February 2025 and was reported missing in early March. On May 17, 2025, his body was pulled from the Ottawa River offshore from Dallaire Street. Following a postmortem, the OPP deemed his death a homicide.
Since June 2026, three individuals have been arrested and charged in connection with this investigation. As a result of the ongoing investigation, two additional people have now been arrested and charged.
On Friday, September 11, 2026, Mathew Blake, 23 of Arnprior, was arrested and charged with:
- Second degree murder, section 235(1)
- Indignity to a dead body, section 182(b)
- Obstruct peace officer, section 129(a)
The accused remains in custody and is scheduled to appear before the Ontario Court of Justice in L’Orignal on Friday, October 2, 2026.
On September 17, 2026, Sebastien Boucher, 47 of Rockland was arrested and charged with:
- Obstruct peace officer, section 129(a)
- Obstruct Justice, section 139(2)
- Accessory after the fact, section 240
The accused remains in custody and is scheduled to appear before the Ontario Court of Justice in L’Orignal on Thursday, September 17, 2026.
The Russell County OPP Crime Unit is continuing the investigation under the direction of the OPP Criminal Investigation Branch, in conjunction with the Office of the Chief Coroner and the Ontario Forensic Pathology Service. Assistance was provided by OPP Forensic Identification Services and OPP specialized units, including the Emergency Response Team, Canine Unit, Aviation Unit, Underwater Search and Recovery Unit and the Snowmobile, All-Terrain Vehicle and Vessel Enforcement team.
Anyone with any information regarding this investigation should contact the Russell County OPP at 1-888-310-1122. Should you wish to remain anonymous, contact Crime Stoppers at 1-800-222-TIPS (8477) or ontariocrimestoppers.ca
