The case against 32-year-old Christopher Cornell is simple, Crown prosecutor Keith Parkkari said this morning in his opening remarks to a Yukon Supreme Court jury.

Cornell and Jessica Johnson broke into the Madley General Store in Haines Junction and stole a safe early on the morning of Sept. 26, 2011, Parkkari said.

He said the two were interrupted by a custodian, who was then punched and sprayed with bear spray.

The custodian, said Parkkari, managed to call the RCMP.

"Miss Johnson and Mr. Cornell were in the parking lot when the police officer pulled up with his vehicle, and they fled in their vehicle down the Alaska Highway,” Parkkari told the jury.

The Crown prosecutor said a chase ensued, and near the end of the pursuit, there was a gunshot toward the police vehicle.

As a result of the gunshot, RCMP Cpl. Kim MacKellar was injured, and the chase ended, Parkkari said in his opening summary of the case.

Shortly before lunch this morning, the nine women and five men of the jury began hearing testimony from 66-year-old Frank Parent, who was working as the custodian at Madley's on the morning of Sept. 26.

Cornell is accused of shooting at and trying to kill MacKellar and conservation officer Shane Oakley, who was in the police vehicle with him during the chase.

He also faces a charge of assaulting the custodian with pepper spray and using violence on the custodian during a robbery.

The trial is scheduled to go for three or four weeks. It's expected 22 witnesses will be called.

Defence lawyer David Tarnow of Richmond, B.C. is defending Cornell.

The accused sat quietly and attentively in the prisoner's dock behind his lawyer as the first day of evidence began.

Earlier this morning, the judge provided his instructions to the 14 members of the jury.

Gower encouraged the jurors to keep an open mind, and to pay close attention to all the evidence.

A jury is the cornerstone of Canada's justice system, and it's the jurors who must determine the facts based on the evidence presented, he said.

"So, in many ways, you are more important judges than I because it will be up to you to judge whether the accused is guilty or not guilty.”

Gower said the presumption of innocence is also a cornerstone of the justice system.

Cornell, he emphasized, is presumed innocent. It is not up to the accused to prove his innocence, and the accused does not have to present any evidence if he chooses not to, Gower explained.

He said it's up to the Crown to prove the charges beyond a reasonable doubt.

The jury, he said, will judge the evidence of the case, and he will judge how the law applies to the case.

After all the evidence has been presented, the jury will be provided with more details regarding the law and how it applies, he said in his instructions.

"You should most of all use your common sense on which evidence you believe and which evidence you do not.”

Gower also instructed the jury to disregard a comment made during Monday's jury selection at the Mount McIntyre Recreation Centre.

At the time, a potential juror said she had knowledge of Cornell having been arrested in the past, Gower recalled.

"That remark was inappropriate and ought not to have been made,” the judge told the jury. "It is not evidence, and you must disregard it.”

He also told the jurors they may have noticed Cornell in leg irons during Monday's selection of the jury.

They are to take nothing from that, Gower instructed.

"You must not conclude that Mr. Cornell is a person of bad character and is therefore more likely to commit the crimes of which is charged,” he said.

"Keep an open mind until all the evidence has been heard.

"Make your decision without sympathy, prejudice or fear. Do not be swayed by public opinion.”

Gower reminded the jurors that Jessica Johnson is the co-accused in the case, but was not in court.

The jury, he said, is to take nothing from her absence; that it is Cornell who is on trial.

"It is now our duty as judges to now sit and listen carefully to the evidence as it is presented to us,” Gower concluded.

"We will now begin the case.”

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