The cause of a fire early Sunday morning is under investigation.
Sarnia Fire and Rescue along with city police responded to a fire at around 3:30 a.m. at 1836 St. Clair Pkwy.
Damage to the modular building and its contents are believed to be substantial.
Fire officials said no injuries were reported.
The Pot of Gold pot shop is also located on the property.
The cannabis store on Aamjiwnaang First Nation has been raided by police at least three times over the past two years.
