HALIFAX -- School officials in four Canadian provinces all received similar bomb threats this week, but each responded to the potential danger differently.
Universities and schools across Prince Edward Island were evacuated Wednesday morning after police received a fax from someone threatening to detonate bombs at several schools. Three colleges in Nova Scotia were also evacuated after receiving threats.
Hours later, a school board in Winnipeg received a similar bomb threat, but no schools were evacuated.
READ MORE: Fax threatens schools in Winnipeg School Division: police
And on Thursday, schools in three regions of Nunavut were closed due to a bomb threat, but reopened after lunch.
"Assessing a bomb threat is very, very difficult," said Chris Mathers, a Toronto-based crime and risk consultant. "You can't examine a bomb threat in a vacuum."
Mathers said a number of factors are considered when assessing the credibility of a bomb threat, including the frequency of the threats and whether similar threats have made.
"If you're getting a bomb threat every day, eventually someone had to make a decision not to act out as the person making the threats wants them to," said Mathers. "And typically, serious bombers don't call it in."
But he said with minimal information available, many officials would err on the side of caution, as was the case in P.E.I.
P.E.I. Staff Sgt. Kevin Baillie said this was the case when the threat was received Wednesday.
"There's no question, the vast majority of these types of threats are not credible. However, in the early stages, it's very difficult to say definitively that the threat is not credible," said Baillie, adding that the decision to evacuate schools was made by the school board.
"It's a very difficult decision to make and I think in the vast majority of cases, it's prudent to err on the side of caution. But no matter what way you go, you're opening yourself up to criticism."
Police in Winnipeg said they were monitoring the threats in P.E.I. and Nova Scotia when a school board there received a similar threat.
READ MORE: Similar bomb threat made to Nunavut schools as threats faxed to WSD
"If the person is making this threat in P.E.I. and Halifax, the likelihood of one individual carrying out the threat as it was described in multiple locations across a country was effectively impossible," said Winnipeg Police Service spokesman Const. Rob Carver.
But officials have the difficult task of balancing the safety of the people being targeted by the threat with creating unnecessary panic, said Carver.
"We don't want to be reacting to one of these a week where we're emptying schools out and somebody thinks this is a joke," he said.
"But our officers always assume we're making life and death decisions. We don't take this lightly. But we also don't take lightly putting a city on panic."
As for the threat in Nunavut on Thursday, RCMP Sgt. David Lawson said officials did consider the similar threats in P.E.I, Nova Scotia and Winnipeg, but decided to search the schools as a precaution.
"We just wanted to ensure all the students were safe," Lawson said.
