The man who found her told police she was cold to the touch, had no shoes on and that there was a belt lying near her body. Gargol died a short time later at a hospital.
It took days to identify her, a task accomplished after police made public photos of her tattoos, along with images of the jacket and broken watch that were found on her body, CKOM in Saskatoon reported.
Antoine initially told police that she and Gargol had gone to several bars before Gargol met a man at one of them and left with him. Investigators said she attempted to lead them on the wrong path by posting on Gargol’s Facebook page several hours after she killed her.
"Where are you? Haven't heard from you. Hope you made it home safe," Antoine wrote, according to the Toronto Sun.
She continued to post on Gargol’s page in the months after the homicide, including on a photo that Gargol posted of the pair just hours before she was slain. The victim made the photo, seen below, her profile picture shortly before she died.
"Aweh, I miss you soo much, Bert! Wish heaven had visiting hours so I could come see you, but I'm so glad you came & visited me in my dream last night," Antoine's comment read, according to CBC News. "Looking forward to that day I see you again. Say hello to my mommy up there for me!"
Police investigators worked the case for nearly two years, using social media to create a timeline for Antoine and Gargol’s movements the night of the slaying. It was that last profile photo on Gargol’s page, however, that proved to be the break they needed.
Detectives noticed that Antoine wore a distinctive black belt, visible around her waist in the bottom left corner of the selfie that she and Gargol took together the night of the killing. The belt in the photo was the one found near Gargol's dying body, CBC News reported.
The photo remained as Gargol's profile picture for more than a year after her death. It has since been changed by her family.
With a suspect in their sights, investigators were able to tear apart Antoine’s story about the pair bar-hopping the night of the crime by obtaining surveillance video from at least one bar that failed to show the girls where Antoine said they were. Another break came when a tip led police to a friend of Antoine’s, who told detectives that a panicked Antoine showed up at her house the night of the murder.
Antoine confessed to the friend that night that after getting into a drunken argument with Gargol, she hit her and then strangled her, CBC News said.
She was arrested on suspicion of murder in March of last year.
A plea deal between prosecutors and the defense brought the charge down to one of manslaughter.
Crown prosecutor Robin Ritter praised the police work that ultimately led to Antoine’s arrest.
“It’s quite remarkable how the police developed this information,” Ritter said.
Antoine admitted in court Monday that she killed her friend, but said she does not remember doing so. Her lawyer, Lisa Watson, told the court that Antoine, who suffered years of abuse in the foster care system, had been dealing with serious personal problems prior to the homicide.
"My client had some very deep, personal issues that she was dealing with, and unfortunately, they turned into a very tragic situation for all involved," Watson said, according to the Sun.
Antoine's troubled past, which began when she became a ward of the province of Saskatchewan at age 2, factored into her plea deal and sentence. CKOM reported that Antoine was in foster care at age 4 and spent a decade suffering physical and emotional abuse.
Her criminal record began with car theft at age 12, two years before she reconnected with her mother, the station reported. She was exposed to heavy drug and alcohol use by her mother, who died about a year after being reunited with her daughter.
At that point, she began moving between relatives, group homes and other institutions.
Ritter agreed with the defense that Antoine has serious personal issues.
"This young woman has issues, and because of those issues, she is dangerous," Ritter said, according to CKOM.
Those issues continued even after Antoine killed her friend. She was reported missing in August 2016 to Saskatoon police officials, who sought information on her whereabouts on Facebook.
At the time of her arrest for murder, Antoine was also awaiting sentencing for threatening a store's loss prevention officer when she was caught stealing, CBC News reported. She threatened the officer with a needle that she claimed was contaminated with the HIV virus.
Antoine issued a statement through her attorney Monday in which she said she cannot provide the answers she knows Gargol’s family members are looking for.
“She knows the family would like an explanation, a reason, but unfortunately, she can’t provide that,” Watson said.
Gargol’s family provided victim impact statements during Antoine’s sentencing.
“Most days we can’t stop thinking about Brittney and what happened that night,” her aunt, Jennifer Gargol, said, according to CBC News. “What she must have felt fighting for her life.”
Gargol's stepmother, Kristi Wickenhauser, also spoke in court, according to CKOM.
“You were her friend. She loved you, she respected you and she trusted you,” Wickenhauser said. “And instead you decided to wrap a belt around her throat and squeeze until you ended her life.”
Antoine apologized to Gargol’s family in the statement read by Watson.
“I will never forgive myself,” she said. “Nothing I say or do will ever bring her back. I am very, very sorry. It shouldn’t have ever happened.”