The Ottawa Police Service arson unit is investigating a suspicious overnight fire at a magic mushroom dispensary on Rideau Street. In a statement to CTV News Ottawa, police said officers were called to the shop on Rideau Street near Dalhousie Street at 3:16 a.m. Thursday on reports of a fire. “The fire was deemed suspicious and the OPS Arson and Explosion Unit is investigating,” police said. The fire was already out by the time emergency responders arrived on scene. The exact cause of the fire is unknown. Ottawa Fire Services investigators will be assisting police, OFS public information officer Nick DeFazio said. Anyone with information who has not yet spoken with investigators is asked to contact the Ottawa Police Arson Unit at 613-236-1222, extension 4587, or via email at arson@ottawapolice.ca. Anonymous tips can be submitted by calling Crime Stoppers toll-free at 1-800-222-8477 or at crimestoppers.ca. This comes after several suspicious fires at magic mushroom dispensaries in September. Police have responded to fires at shops on Bank Street, Preston Street, and on Rideau Street, across the road from the site of Thursday’s fire. The Sept. 8 fire at the Rideau Street dispensary involved an SUV that had crashed into the front of the store and caught fire. In the past month, Ottawa police have been executing search warrants at several magic mushroom shops in the city, seizing multiple kilograms of psilocybin products and laying drug trafficking charges.