New citizen's arrest powers came into force on Monday, giving ordinary Canadians more room to collar criminals.
The amended version of the Citizen's Arrest and Self-defence Act has one important change – people can make a citizen's arrest within a "reasonable" amount of time after a crime has occurred, rather than when catching a perpetrator red-handed.
Here's more on the new law:
What is a reasonable amount of time?
As with other laws involving measures of reasonableness, legal experts say it will ultimately be up to the courts to assess the timeliness of citizen's arrests.
"It's not based on any definable criteria. I think it is very subjective and will be a case-by-case determination because someone can walk into a store a year later. Is that reasonable? Is three weeks reasonable? I'm not really sure what it means," said Alan Young, a law professor at York University's Osgoode Hall.
The Canadian Civil Liberties Association had wanted an outside limit of 24 hours on citizen's arrests, saying such a specification would provide better guidance.
What about the police?
Citizen's arrests are only allowed when it is "not feasible" for a police officer to make the arrest.
As well, the law requires anyone making a citizen's arrest to call the police and deliver their arrestee without delay.
"If a person making a citizen's arrest does not call the police as soon as possible, the arrest might be ruled illegal, and there could be civil or criminal consequences for the person making the arrest," according to a government document explaining the law.
But it's unclear whether, say, shopkeepers must call 911 before making citizen's arrests of suspected shoplifters or whether they can call the police afterward.
How will this affect private security companies?
The Canadian Civil Liberties Association believes that the new law will mostly be used by private security guards investigating shoplifting in malls – and worries about possible abuses of power.
"The concern is that now it gives them the power to not only check whether you have something in your purse … now it will give them the power to arrest you on the grounds that they reasonably believe it was you yesterday, or two days ago, or last week, or this morning who stole something. And the arrestee has very little ability to debate them," said Nathalie Des Rosiers, general counsel of the Canadian Civil Liberties Association.
"It's the abuse of the power that we're concerned about and whether it will on the ground lead to some excesses."
Could this lead to vigilantism?
Some legal observers worry that it could. Ms. Des Rosiers said people could use the powers of citizen's arrest to make false accusations against others.
"The concern is will it be applied and will it be used in contexts where it could expose citizens to dangerous situations, lead to violence, lead to forms of vigilantism or simply just be unsafe for everyone concerned?" she said.
Will the amended law lead to a rash of citizen's arrests?
Likely not, given they are relatively uncommon.
Even the government, which trumpeted its new law, is warning of the risks inherent in such an action.
"A citizen's arrest is a very serious and potentially dangerous undertaking," it says. "Unlike a police officer, private citizens are neither tasked with the duty to preserve and maintain public peace, nor properly trained to apprehend suspected criminals. Exercise extreme caution when attempting to make a citizen's arrest."