SASKATOON — Dr. Ernie Walker credited the City of Saskatoon's garbage collection and disposal system with helping solve the case of Mackenzie Trottier, whose remains were found at the city's landfill and recovered last week.
Walker, a professor emeritus at the University of Saskatchewan, is a forensic anthropology expert who helped the Saskatoon Police Service search the landfill for Mackenzie Trottier's remains. Their 93-day search ended on Aug. 1, when Trottier's remains were recovered.
The police labelled the case closed since the lone male suspect died of an overdose in December 2023. The Saskatchewan Coroners Service is continuing the investigation to determine Trottier's cause of death.
The landfill became the focus of their investigation after the police obtained a warrant to search the suspect's mobile phone data. The suspect lived in the 1300 block of Avenue B North, and the data showed a high search history on the city's garbage truck pick-up schedules.
Sgt. Joel Bautista approached Walker to assist. Walker said he was initially skeptical, having assisted in other cases where investigators searched landfills. However, the information the police obtained from the mobile phone data, not from other sources or informants, was the game changer as it pointed to a particular location: the landfill.
"I had searched that particular landfill twice and other more complicated ones elsewhere. When we went out and had a look out at the locale, I could see that it was going to work. In terms of facilities [landfill], that concrete pad is everything because most of the time you are on flat ground," said Walker, who also trains law enforcers in forensics.
"You want to create what's called a monolayer, where you take all the trash, disperse it, lay it all out so it is not very thick, and that gives you a better chance of seeing something. As I said, wandering through trash will not be enough."
He said Saskatoon carefully manages its waste, describing how tracking the fleet of garbage trucks and their collection schedule in each community was the key to finding Mackenzie Trottier. SPS contacted Teresa Dyer, the city's Fleet Services Operations Assistant, for the trip logs and the GPS tracking in the landfill area where they dumped the garbage collected.
"Those trucks have GPS, and we know where they dump, but as I said, trash moves around. The reason is that the landfill in Saskatoon is finite and will not get bigger in terms of area so that it will go higher. To do that, you need to compact the trash so it would hold the weight of whatever is above it," said Walker.
"You do that by tracking how much is going in there daily. We had information on where that might be, which is the key. [We] were not going in blind. The original area expanded quite a bit, three times, just because things were moving around, voids got filled in, and it was not exactly in the position you might think it was."
Still, the process was not easy, even with them knowing where to search. They faced the prairies' ever-changing weather and sifted through tonnes of garbage in the landfill, including sharp and pointed objects. Forty-four officers from SPS's Public Safety Unit were involved in the search with the help of trained dogs.
"We know the surface area where we are looking, but we do not know the depth. This is extremely complicated, and you have to look at your staff. As it turned out, the facilities at the [landfill] were perfect for a search like this, especially a concrete pad where the actual search could occur," said Walker.
"There were difficult conditions; sometimes, it is disheartening when you're not finding anything. You can not stay out searching all day. We have to rotate people because the tendency is you will lose concentration. On the one hand, it was a good search regarding facilities. It was planned for a month and went on for three months."
He added that he called a place "the hill" where trash and thousands of bone fragments would fall in the search area. In terms of what was found, it was what he was expecting, which could have been one reason why the search took that long.
"It was a righteous search. This was one of the best examples of a large-scale search I've been involved in for 40 years. Thank you to all the support staff in the command post and my colleagues. The Saskatoon Police now has more experience in this kind of operation than any other unit I can think of in the country and even in North America," said Walker.
"This does not happen very often. ... I want to let the citizens of Saskatoon know the exceptional nature of this search and the dedication of my colleagues to that search and the outcome to give closure to the Trottier family."
The search to recover Trottier's remains took 93 days, which was a time of hope and uncertainty for her family, who had patiently waited for almost four years to bring closure to her disappearance. Trottier was last seen alive in December 2020 and is believed to be in the suspect's residence in the 1300 block of Avenue B North.
During that time, those involved braved snow and rain that made conditions at the landfill wet and muddy, wind gusts reaching 70 kilometres per hour, and temperatures reaching 34 degrees Celsius. They also sifted through an estimated 5,000 metric tonnes of garbage.
SPU members made a partial recovery of human remains on July 30, Tuesday, after a thorough search of a calculated area of the landfill. A continued search resulted in a full recovery on Aug. 1 and, after consultation with Walker and examination of the dental records, it was confirmed that it was indeed the remains of Mackenzie Trottier.
KBL Environmental helped in the excavation process, while the North Saskatchewan Regiment of the Canadian army, whose headquarters are in Saskatoon, supplied the gear and tents used by Walker, the PSU search team, the City of Saskatoon engineers, the Calgary Police Service, and the RCMP.
