The 21-year-old Canadian woman who was sentenced earlier this week to seven years in prison for killing her best friend did not succumb to police questioning, insisting she was innocent even as they presented her with the photographic evidence that helped seal her fate.
Cheyanne Rose Antoine from Saskatoon, Saskatchewan, ultimately pleaded guilty Monday to using her own belt to strangle Brittney Gargol in 2015. Gargol’s body was found on a road leading to a Saskatoon landfill.
When investigators revealed the Facebook selfie showing her wearing the murder weapon around her waist, Antoine steadfastly maintained her innocence.
“Her reaction was maybe unusual for someone so young,” Saskatoon’s Senior Crown Prosecutor Robin Ritter tells PEOPLE. “She held it together. She held it in. She never displayed emotion or remorse. In other words, she was questioned but she never admitted it and that’s hard for people.”
Ritter adds: “Most people, when confronted with a serious crime, they have an emotional reaction. She didn’t.”
She told detectives she had been drinking with Gargol the night of her death, and that the two got into an argument. While Antoine admitted Monday to killing Gargol, she said she has no recollection of the killing.
Six hours before the killing, Gargol shared a photo of the pair smiling on her Facebook page. In the photo, Antoine wore a large belt — the same belt that was used to kill Gargol.
The belt was recovered by police, who found it beside the body.
The selfie, Ritter says, “was a very important piece of evidence,” but there was much more to the prosecution than that single image.
“The accused went to great lengths to try to mislead police and steer them in the wrong direction,” Ritter tells PEOPLE. “She manufactured a false alibi, placed the blame on other people, generated false suspects, was following up with [Facebook] posts saying, ‘I hope you made it home safe’ … she knew she didn’t because she killed her.”
Ritter says “it was a complicated case for the investigators,” and adds that “they did a remarkable job, going from practically nothing to making an arrest and ultimately, [Antoine] accepting responsibility for the murder.”
The case now closed, Ritter says one part of the proceedings with stick with him forever.
“Brittney had a sister who is a little girl; she was maybe 5 when Brittney was killed,” Ritter says. “It is very, very hard on that little girl. She wrote a letter as part of her victim impact statement, and it included a drawing — a crayon drawing of a rainbow. She said Brittney was her rainbow. That…that hits you.”
This article originally appeared on PEOPLE