Canada's top law-enforcement official has implored police to reassess how they manage sex-assault complaints, as the country's second-largest force joined several others in mounting a full-scale audit of every case closed as "unfounded" – a formal classification that deems allegations baseless.

Public Safety Minister Ralph Goodale made the demand on Tuesday, as three major police forces launched reviews into their handling of sexual-assault complaints in response to a Globe and Mail investigation that exposed deep flaws in the way investigators treat such allegations. Mr. Goodale called on police investigators and Crown prosecutors "to re-examine all of their approaches, all of their procedures, all of the ways that cases are managed, that investigations are conducted to make sure that we fix this problem and that our criminal justice system is delivering justice to those who in these circumstances have been so brutally victimized."

On Tuesday, the Ontario Provincial Police, Saskatoon Police Service and York Regional Police all said they would be reviewing sex-assault complaints that have been dismissed as unfounded, bringing the confirmed number of forces undertaking reviews to seven. A Globe analysis of data from more than 870 police jurisdictions found that investigators dismiss one out of every five sex-assault claims as unfounded. Independent research from around the world suggests the actual rate of false reports lies somewhere between 2 per cent and 8 per cent.

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Read more: Unfounded: How police and politicians have responded to The Globe's investigation so far

Read more: Unfounded: Police dismiss 1 in 5 sexual assault claims as baseless, Globe investigation reveals

The findings of a 20-month long investigation expose deep flaws in the way Canadian police forces handle sexual assault allegations. The Globe's Robyn Doolittle explains.

Read more: Will police believe you? Find your region's unfounded sex assault rate

Read more: Ottawa calls for overhaul of how sexual-assault cases are handled

When an allegation is designated as unfounded, it is not reflected in any local or national statistical records. The Globe data found that 115 forces were rejecting at least one-third of all sexual-assault complaints they received.

The largest force among them was the OPP, with an unfounded rate of 34 per cent, according to The Globe analysis, a finding that spurred the country's biggest provincial police service to action on Tuesday. "The OPP is reviewing sexual assault investigations and outcomes on a detachment-by-detachment basis," OPP spokesman Sergeant Peter Leon said. "This is going to take a period of time to take place."

While Sgt. Leon could not provide further details concerning the audit's scope, such as the number or time-frame of cases under review, he said all of the OPP's 163 detachments would be under scrutiny. The OPP's records management team is already comparing The Globe's data with internal figures. Until that process is completed, the OPP won't comment directly on its unfounded rate or why it is so much higher than the national average.

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"It's all still fairly fresh," Sgt. Leon said. "The article was only printed this past weekend. We are still looking fairly closely at it. The process has commenced. Like I say, it will take some time for us to work through our data and look at the data that was shared in The Globe's article."

He did address questions about the expertise of OPP personnel, saying all investigators assigned to sex-assault cases complete a one-week "special investigator's course" taught through the force's police academy. "They do respond appropriately to the immediate and long-term needs of our victims," he said. "At the end of the day, if somebody has been a victim of this type of crime, they need to know that the OPP treats these incidents very, very seriously and they put their best resources behind investigations that do take place."

The unfounded rate for sexual assault swings wildly from city to city. Toronto Police Service, for example, posted a five-year unfounded rate of 7 per cent. Hop across the city's northern border to York Region, however, and the rate jumps to 31 per cent.

A York police spokesman said on Tuesday the force is working to address the issue. "York Regional Police is reviewing cases of sexual assault that were cleared unfounded and we are also examining the definition of the unfounded clearance code as it relates to sexual assaults," Constable Andy Pattenden said.

The Globe reached out to the country's 25 largest police jurisdictions for reaction to Mr. Goodale's comments and the mounting pressure to re-evaluate old sex-assault complaints. Most remain non-committal. Both Montreal police and Quebec provincial police, the Sûreté du Québec, said they have no plans for a systematic review of unfounded files.

In Ottawa, where the unfounded issue was brought to the attention of the local police service by advocates and academics in the city about four years ago, Inspector Jamie Dunlop said the department has already overhauled its coding and training procedures.

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In 2012, Ottawa police closed 38 per cent of sexual assault cases as unfounded. In 2016, that number was down to 8 per cent, said the inspector, who oversees major investigations such as sex crimes and homicides.

Going forward, Insp. Dunlop said the force will continue to work on training, to make sure officers are "recognizing signs of trauma and more importantly, not misinterpreting signs of trauma."

Speaking about the unfounded issue in general, Insp. Dunlop said he thinks many police officers aren't thinking about the fact that once a case is cleared as unfounded, it is no longer counted and reported to Statistics Canada.

"I just learned that a few months ago," he said. "Police officers are not statisticians … I just don't think it's even in their minds that that's why they're doing it because it won't be counted."

Nationally, the RCMP has said it is exploring the issue.

At the other end of the scale, the police chief of Amherst, N.S., population of about 9,500, vowed to investigate his department's five-year unfounded rate, pegged at 49 per cent.

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"We know our percentage is in the high end," Chief Ian Naylor said, "however, we must gather more detailed information to determine why and identify any follow-up action required."

Before calling for a national case review, Mr. Goodale reiterated the wider importance treating sexual-assault complaints fairly. "I think in the wake of that story, everyone has become even more highly resolved to make sure that these cases are properly and effectively dealt with and nobody feels deterred from coming forward with a complaint for fear that they might not be treated seriously or in a respectful manner," he said. "There's no excuse for that, and we need to make sure that our system is strong and has the kind of integrity and effectiveness that victims have every right to expect."