And that's the key, 'the story is'. I wonder, would a floor plan of the Horton's and the time of detonation be important to sorting this out? It has happened here in the deep South that a 'fry station' under an industrial hood was used to cook up Meth during 'store closed' hours. Some explosives have poisonous gases as by products during 'cooking'.
Unless that one is some weird exception, Tim Horton's are open 24/7.
MG, I respect your curiosity, but you are barking up the wrong tree, I think. Let's see if we can find this guy's identity. It would explain a lot.