The assault trial for Const. Geoff Mantler opened Monday with testimony from the journalist who caught him kicking a kneeling suspect in the face.

Kelly Hayes stood across the street from Mantler during the Jan. 6, 2011 arrest, filming with his iPhone as the officer stepped towards 51-year-old Buddy Tavares and punted him.

The video made headlines across Canada, leading to a charge of assault causing bodily harm for Mantler and inspiring a protest rally against the RCMP in Kelowna.

But the same footage may play a large part in the defence’s strategy.

During Hayes’ cross-examination, Mantler’s lawyer broke the footage down frame by frame and highlighted a fifth of a second in which Tavares appears to raise his hands slightly towards the officer.

“When you see it in plain speed, in normal speed, you wouldn’t notice that until someone breaks it down,” Hayes told CTV News. “But it can’t be denied that Mr. Tavares raises his hands.”

Tavares, who spoke briefly on his way into court, said he expected his character would play a key role in the defence.

“His whole defence is going to be to discredit me, you watch,” said Tavares, who says he suffers ongoing anxiety attacks as a result of the kick.

Tavares’ truck was pulled over the day of the alleged assault by Mounties responding to reports of shots fired at the Harvest Golf Club. A friend of Tavares told CTV News he was on disability leave from his job at the course at the time, and that one of his duties had been scaring off geese with a shotgun.

Mantler pleaded not guilty to the assault, a move that still shocks Tavares’ family. The officer declined to speak to reporters outside the courthouse Monday.

He has been suspended from duty since January 2011 and had his pay revoked months later.

The trial is expected to last two weeks.

With a report from CTV British Columbia’s Kent Molgat