Warshaw’s point is that officers have a duty to try alternatives to lethal force.

When defence lawyer Peter Brauti began his cross-examination of key prosecution witness Robert Warshaw, it was with the acerbic suggestion that Warshaw was little more than another Monday-morning quarterback.

“That is not what we’re to be doing when evaluating use of force by police, is it?” Brauti asked.

It was but the opening volley of a long and aggressive cross of Warshaw, who is testifying as a use-of-force expert and who has told Ontario Superior Court Judge Ed Then and a jury that, in his opinion, teenager Sammy Yatim posed absolutely no threat to Toronto police Const. James Forcillo when the officer fatally shot him.

Warshaw stuck to that opinion Thursday, repeatedly disagreeing with Brauti that when the first shots were fired, Yatim was advancing forward, and thus precipitated the shooting.

Forcillo is pleading not guilty to second-degree murder in the July 27, 2013, death of the 18-year-old on a downtown streetcar.

Jurors have seen extensive video of the shooting, which saw Forcillo fire nine shots in two volleys at the teen. Minutes before, Yatim had exposed himself and, with his penis in one hand and a switchblade in the other, swung the blade unprovoked at a young girl.

By the time Forcillo and his partner arrived, Yatim was standing at the front of the streetcar, still holding the knife. He then moved away from the front a bit, and with Forcillo now warning him not to come forward again, Yatim took one step and was taking a second when he was shot.

“I disagree with the term ‘advancing ’ and what it implies,” Warshaw said several times. “He’s not in my judgment coming forward; he moved.”

Earlier, finishing his examination-in-chief by prosecutor Milan Rupic, Warshaw also suggested that Forcillo should have reassessed the situation before letting loose the second volley of shots.

“He (Yatim) was certainly contained,” he said. “He was on his back. He was in need of medical attention.”

Warshaw said the threat Yatim then posed was “negligible,” and that it should have been apparent to the officer that “he’d been hit by hollow-point bullets and his mobility was at best spasmodic.”

Brauti attacked Warshaw’s credentials, pointing out that he’d never before been qualified as an expert in court and that there were some holes in his knowledge about how Forcillo had been trained (Warshaw, for instance, did not realize that all officers in the province are trained first at the Ontario Police College) and that he’d never been certified as a use-of-force instructor.

“Your lack of practical experience is a problem in this case, isn’t it?” Brauti asked once, to which Warshaw replied, “I strongly disagree.” A former police chief in several U.S. cities, he works mostly as a court-appointed “monitor,” making sure problem police forces that are ordered to clean house and reform do so — and many of the problems these forces have relate to excessive use of force.

As he told Brauti at one point, agreeing he isn’t personally making use-of-force decisions anymore, “What I do for a living is evaluate those who do.”

Warshaw’s chief criticism of Forcillo is that in failing to recognize that time was his greatest ally, he availed himself of virtually no de-escalation techniques and didn’t, for instance, try to talk Yatim down by engaging him conversationally. But under Brauti’s questioning, Warshaw agreed that giving loud shouted commands such as Forcillo did (“Drop the knife!”) and issuing a specific warning to Yatim that if he came forward Forcillo would shoot him are considered de-escalating techniques according to Toronto police (and other forces’) training.

In fact, in some U.S. states, police are required by law to tell suspects they are considering lethal force before they use it.

Warshaw’s objection to the I’m-going-to-shoot-if-you-do-that warning is that it may become “a self-fulfilling prophecy ... the officer ... could feel the need to fulfil what he said he’d do.” More interesting, perhaps, is how differently the witness and the lawyer fundamentally view policing.

Brauti, for example, made light of several options Warshaw mentioned that Forcillo could have considered — such as throwing a baseball or a police baton at Yatim to disorient him.

“You’re mocking what I’m saying,” Warshaw said once.

“I am,” Brauti cheerfully admitted. But Warshaw’s point is that police officers have an affirmative duty to try alternatives to lethal force — even baseballs, if necessary — because the fundamental police obligation is the preservation of life. While Brauti was pointing out the flaws in some of Warshaw’s suggested alternatives to lethal force, Warshaw replied, “I don’t think any police officer believes everything they do is 100 per cent safe ... (taking some risks) ... is how they preserve life.” And many officers, he said, are remarkably creative at doing that.

“With these ‘reasonable’ and ‘safe’ ideas you bring to the table,” Brauti asked, “you had months and months to think about this?” “Yes,” said Warshaw. “As much time as you wanted?” “As much time as I wanted.” “A lot more time than Officer Forcillo?”

“Yes,” said Warshaw. His crossexamination will finish Friday.