Hours before four young men and women were gunned down on a lonely stretch of Alberta highway, one of them, Tabitha Stepple, had been involved in an angry confrontation with her ex-boyfriend, believed to be responsible for the shootings.
In a chilling scenario outlined Friday by friends and sources close to the victims, the jealous rage of the former boyfriend, identified as Derek Jensen, led him to tail Ms. Stepple as the four drove toward the Calgary airport.
A few kilometres north of the small community of Claresholm, in the early hours of Thursday morning, he forced Ms. Stepple's vehicle off the road. He shot the four people inside, three fatally, then killed himself.
At the scene of the shootings, Mr. Jensen's Pontiac Sunfire could be seen with a dent in its passenger side, while the back and driver's windows of Ms. Stepple's car were shattered.
Killed were Mitch MacLean, 20, Tanner Craswell, 22 – two college ballplayers from Prince Edward Island – and Ms. Stepple, 21.
Shayna Conway, also in her early 20s, survived the attack and is recovering in hospital. Police said Saturday she was driving Ms. Stepple's vehicle.
The altercation between Mr. Jensen and Ms. Stepple took place at a local bar in Lethbridge, where a number of friends had been celebrating the 22nd birthday of Mr. Craswell, a source who knew the celebrants told The Globe and Mail.
The source said Ms. Stepple ran into Mr. Jensen, who "freaked" when he saw her at the pub.
Cait McFarland, a close friend of Ms. Stepple's, told CTV that Mr. Jensen pushed her out of her chair and yelled at her.
"Then we left. He was phoning her, phoning her, phoning her, and said to her, 'This night's not going to end well for you. I hope you know that,' " Ms. McFarland recounted.
RCMP Sergeant Patrick Webb said police investigators are still working to determine, with certainty, a reason for the killings, but acknowledged "a domestic violence, jilted-boyfriend motive" is under consideration.
The two slain young men had been on their way to the airport to catch a flight back home to Charlottetown for Christmas.
They had spent the past year or so in Lethbridge, attending school, going to the local Prairie Baseball Academy and playing summer ball.
Their fateful ride to the airport came close to having a different ending. Kevin Kwame, the pair's landlord and head of the Lethbridge Bulls for whom the victims played, said he had offered to drive them to the airport the night before. "That was the plan."
However, the players decided to stay an extra night in town to celebrate Mr. Craswell's birthday, when Ms. Conway, his girlfriend, managed to line up a ride with Tabitha Stepple.
"Those boys had nothing to do with [Derek Jensen] They were in the wrong place at the wrong time," Mr. Kwame said, with emotion.
Greg Vavra, whose son, Tyler, roomed with Mr. Craswell in 2009-10, described the victim as "mature beyond his years. He had a competitive spirit that was brilliant. He was a guy you wanted on your team."
Mr. Vavra was travelling back to Calgary on Thursday along Highway 2, and had to be detoured past the crime scene while RCMP investigated.
"I had no idea [what had happened] none whatsoever. Tanner was very attached to Shayna. They were soul mates."
People who knew the gunman were stunned by what happened.
Adrian Edwards, who played football and went to high school in Lethbridge with the young man, remembered an ordinary guy with good grades, not a gun enthusiast as indicated by his Facebook page.
"This is a complete shock," Mr. Edwards said.
"This is a complete 180 from the kid I knew," he said.
Meanwhile, back in Prince Edward Island, Reverend Eric Lynk had the heavy task of helping tell Irwin and Dianne MacLean that their son, Mitch, would not be coming home for Christmas.
The MacLeans' small, trim bungalow in Winsloe South near Charlottetown was brightly decorated for the festive season when Mr. Lynk knocked on the door, accompanied by police.
"It's an awful message to bring, and then you immediately start to offer support without falling into cliché," he said.
"It's not a time for preaching. I did none of that. I symbolically embraced them, as they experienced every possible emotion they could ever express."
With reports from Dawn Walton in Calgary and Wendy Stueck in Vancouver