St-Louis retired in August 2015. He last served as a master warrant officer (MWO) in Kingston, Ontario.
After the retired veteran went missing his wife called police. They say the investigation is still ongoing as of Monday morning, and police have put out notices for St-Louis's whereabouts.
"Still looking for him," confirmed Sgt. Jeff Pallister with St. Thomas police. "It's being treated as a missing person."
St-Louis's car is a burnt orange 2008 Ford Escape with Ontario license plate number BSCA 395.
Police say he has a history with PTSD. They are asking people to keep and eye out for him or the vehicle and to report anything they see immediately.
"As far as the status is, as you know, some people want to stay missing," Pallister said. "But we're using everything we can to try and find the person."