Brandan Leeson told the court he reached that conclusion when he reviewed security videotapes of the Aug. 28 incident that occurred just before 1 a.m. at the Esso station on Highway 108 North.
The five-year officer said he could see the man's facial hair — a scraggly goatee and unshaven moustache — long slender face and medium length hair.
The man was wearing sunglasses, a red hoodie and red pyjama pants.
"It's Alex Ethier, based on my observations when I saw him Aug. 20," Leeson told prosecutor David Didiodato on the second day of the accused's trial.
Ethier, 25, has pleaded not guilty to robbery while armed with a knife, carrying a weapon to commit an offence and uttering a threat to cause bodily harm.
Superior Court Justice Ian McMillan heard Leeson had an 11-minute conversation with the accused when he did a well-being check on him.
He described Ethier as unshaven, with a scraggly, unkempt orangish-red goatee.
During cross-examination, defence counsel Jennifer Tremblay-Hall suggested the video doesn't clearly show the robber's face.
Leeson disagreed, saying his identification was based on the totality of what he saw, and that he could "absolutely" do that based on the 11 minutes he had spent talking with the accused.
He said he examined the video frame by frame and was able to discern the orangish-red colour, and in "the totality I can see that."
Tremblay-Hall asked him to show the court one particular image that clearly showed this.
"I can not pick the exact moment," he said. "If you look at it as a whole (you can see it)."
Leeson was one of the first officers who responded to the robbery call.
After speaking to the clerk, he left to look for the man who had fled the scene in a black GMC truck.
He testified that he drove around town, targeting certain areas where he had previously seen this vehicle but didn't locate it.
The constable said he associated it with Ethier, who was a suspect in other robberies and had a history of convictions for such offences.
"The only person you suspected from the moment you got the information about the black truck was Alex Ethier," Tremblay-Hall suggested.
"Yes," Leeson replied.
The court also heard from Det. Steven Groot, who reviewed the video showing the truck pulling up to the gas pumps.
The vehicle had "Rough Country," written in white on the rear window, he said.
Groot was able to focus on the licence plate and discovered Ethier was the owner of the truck.
He also searched the pickup after Ethier was arrested on Aug. 31 by Sudbury police.
There was a lot of garbage strewn in the box of the truck, and an empty pack of Number 7 Red cigarettes was located there.
Two other kinds of cigarettes were found in the cab.
Four packs of Number 7 were taken in the robbery.
During cross-examination, Groot indicated there were no forensics, DNA or fingerprints tying Ethier to the robbery.
As well, the knife was never found.
When Tremblay-Hall referred him to the video of an interview he conducted with Ethier following the arrest, the officer described the man's facial hair as more than two days of growth and dark in colour.
On Thursday morning McMillan heard from the accused's older sister — the only witness called by the defence.
Josee Ethier testified that she doesn't recognize the person in the robbery video.
"It bothers me he is accused of this. It looks absolutely nothing like him," she said, indicating she based this on the part of the man's face she can see in the video.
The person has a lot of dark facial hair and her brother's hair is blond and doesn't grow in that way, Ethier said.
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