The man who wrote the book on police training for dealing with people with mental health issues says the rules change as soon as a weapon or a threat is identified.

Ron Hoffman told a coroner’s inquest Thursday that when facing someone with a mental illness, if they don’t pose a danger to the public or themselves, police try to engage them.

But when there’s a threat, like a knife, police should disengage, call a tactical unit, or a supervisor with a Taser.

Hoffman said research shows there’s a 50 to 70 per cent increase in the risk of violence if the suspect is diagnosed with a major mental disorder.

“You’ve got to train the officer to think, this is not just another call,” he said.

Hoffman asked to help draft training procedures for police forces after the inquest into the fatal shooting of Lester Donaldson.

Donaldson was shot by police in 1988. An inquest six years later recommended police develop resources to better deal with persons suffering mental illness.

Lawyer Peter Rosenthal pressed Hoffman on why police don’t try a softer approach. Hoffman said when a knife is present, communication doesn’t end, though officers can’t predict what will happen.

"You’re talking about de-escalation as if there’s some hard science out there that says de-escalation involves X number of strategies, we don’t know," Hoffman said.

Hoffman said training should be standardized across the country. But when lawyers asked if more training was the answer, Hoffman said he didn’t know if it would translate to better outcomes on the front lines.

Woman asks if Taser could have saved sister

The inquest is examining the deaths of three people, including Sylvia Klibingaitis, who was shot dead by Toronto police on Oct. 7, 2011. She had called 911 telling them she had a knife and wanted to kill her mother.

The inquest is also looking in to the shooting deaths of Michael Eligon and Reyal Jardine-Douglas. All died after confrontations with police in the past three years. All were suffering from mental health issues and each was holding a sharp object when shot.

Earlier in the day, Wasowicz asked police trainer John Zeyen if her sister would still be alive today if officers had a Taser.

Zeyen said that in a similar hypothetical situation, Tasers wouldn’t have changed how police responded.

"Theoretically, in a lot of cases, when a knife is being used to threaten or assault a police officer, generally speaking [a Taser] wouldn’t be appropriate…. Generally speaking it wouldn’t replace a firearm."

Wasowicz expressed surprise at the answer, commenting that she believes there’s a public perception that Tasers could help avoid tragic results to standoffs involving suspects suffering from mental illness.

“I can’t stress enough, this is a huge, shocking piece of information for me,” she said.

She wondered how many relatives of people suffering with mental illness, would call police believing "there’s a higher probability of survivability" if Tasers were deployed more widely.

Wasowicz suggested there should be more public education on the limitations of the devices.

Given that the province has recently allowed wider use of Tasers, Wasowicz also suggested more resources be put into dealing with mentally ill suspects, rather than Tasers.

Giving evidence for the second day, Zeyen has discussed a number of limitations the devices have in high-risk situations. He also told the inquest the choice to deploy the device is never simple.

"I think the [Taser] is a good tool, we really have to put a lot of effort to it being used reasonably, based on the situation, but it’s also based on what officer is using it and in what situation."

The inquest continues Friday.