Chinese shopkeeper defeats two robbers - video
Zhen Yang managed to detain one of the suspects with the help of a customer after they threatened him with knives. Yang used bear spray as a weapon.
Gatineau police sergeant Jean-Paul Lemay said: "People are allowed to defend themselves, but we don't recommend the use of force when you're dealing with someone who could potentially be violent."
Police took one suspect into custody on Tuesday night, and brought in his alleged partner in crime on Wednesday. Lemay added that citizens who intervene in crimes in progress should know that even a citizen's arrest can lead to a charge of excessive force.
He said: "The use of force, just like police officers, is allowed, but it has to be reasonable. Anyone could face charges like police officers can when they use excessive force. It's the same rules and regulations for everyone."
Tom Stamatakis, who heads the Canadian Police Association, said: "It can be a big deal to lose $100 when margins are tight, but nobody wants to see someone get seriously hurt or even killed over trying to protect some property or the theft of what, in the context of a life, is a relatively small amount of money.
"You don't know what you're dealing with. These people often have some sort of psychosis, either relating to drugs or intoxication, or they could have some mental health issues. In some cases they could just have a complete disregard for anything they might do that would have an impact on someone."
Stamatakis pointed to the number of assaults on police officers, who are armed and trained in the use of force. "They will go to great lengths to get away," he said. "These are people who will take on a trained police officer; it's nothing to them to take on a shopkeeper."