When Peter Khill shot Jon Styres in his driveway in the middle of the night, the former reservist could have been acting on training as ingrained as riding a bicycle, says a psychologist.

Laurence Miller took the stand in the Khill trial Friday as an expert witness called by the defence.

When someone is trained repeatedly in an action, Miller said, it changes the person's brain structure. So they remember it years — even decades — later.

Common examples, he said, include driving a car, eating with utensils or riding a bicycle.

The same goes for reservists who have been trained to "neutralize" threats, Miller said in Hamilton Superior Court. That may explain why Khill grabbed a gun when he heard someone outside his Hannon house around 3 a.m.

"People can remember to do things they learned decades ago," Miller said. That action memory explains the term "as easy as riding a bicycle."

With soldiers and officers, Miller said, that includes "neutralizing" a threat.

"You want to be able to see it coming before it's on top of you," said Miller, who trains U.S. law enforcement officers.

"You want to neutralize a threat before it neutralizes you."

Khill has pleaded not guilty to second-degree murder in the shooting death of Styres on Feb. 6, 2016. Miller was the last witness.

Prosecutors say Styres was trying to steal Khill's 15-year-old truck. Khill, 28, admits to grabbing a 12-gauge shotgun from his bedroom and running outside in a T-shirt and boxers.

Styres, a 29-year-old man from the Six Nations reserve, was shot by two close-range shotgun blasts.

Khill has testified that when he heard someone outside, lessons from his four years in the Canadian Armed Forces reserves came flooding back.

Crown attorney Steve O'Brien says Khill could have just have called the police instead.

Evidence earlier in the trial was that Khill joined the 56 Field Regiment based in Brantford in 2007 and left in 2011.

He was mostly considered a part-time soldier. Testimony by Walter Sroka, Khill's superior officer in the regiment, was that his involvement was on a weekly basis (3-4 hours per week) but he also participated in weekend exercises and longer-term exercises during summers.



He testified that Khill took the introductory Canadian Forces course which covered how to march, army history and how to use his rifle. He also took a 1-month soldier qualification course, which covered the nuts and bolts of being a soldier - using different weapons including the machine guns, grenades, rocket launchers, etc. It also included day and night exercises.



He did participate in a military operation during which he was considered full-time. He was part of the security detail during the G8 Summit in Huntsville where Sroka said the soldiers underwent intensive training on how to deal with civilians and worked 24/7 with police.

O'Brien did not cross examine Miller Friday.

Miller's brief testimony was the last before Manishen and O'Brien begin closing arguments Monday. Jury deliberations could begin Tuesday.