In the movies, it’s a show of force.
Swarms of heavily-armed police officers jumping from moving vehicles, helicopters battering above yellow tape, barking dogs and wild chases.
In reality, a manhunt is methodical, according to Dave Perry, a former Toronto police detective-turned-private investigator.
Prioritization, he says, is key.
“You prioritize all your tips, your information, and you go to their last location,” he said.
A Canada-wide manhunt is underway for two B.C. teenagers charged with second-degree murder in the death of Leonard Dyck of Vancouver, and suspected in the double homicide of Lucas Fowler of Sydney, Australia, and Chynna Deese of Charlotte, N.C.
The pair, who were originally considered to be missing, have been on the move.
RCMP believe 18-year-old Bryer Schmegelsky and 19-year-old Kam McLeod were in Meadow Lake, Sask., on Sunday — two days after their truck was found abandoned in Dease Lake, B.C.
WATCH: Greater police presence deployed in Gillam, Man. to locate suspects connected to B.C. murders
Since then, police believe they were in Gillam, Man., more than 1,000 kilometres away. On Wednesday, the RCMP said a second vehicle used by the suspects was found abandoned in the area after a report of a vehicle fire.
Police have asked the public to stay vigilant and report anything suspicious, but are urging people to leave the investigation to the investigators.
Perry said investigators likely had a working theory shortly after they discovered the bodies of the two tourists on July 15. From there, “behaviours patterns” and background information about the suspects would be analyzed.
It’s tracking the perpetrators that’s the difficult part.
“In reality, all you can do is go to where they last were and follow the trail,” Perry told Global News Radio 640 Toronto guest host Tasha Kheiriddin.
“Visiting each place where they’ve been, there’s usually some form of evidence, whether it’s video or forensic or otherwise, that will give an indication of what their next move might be.”
The difficulty in this case, in particular, is the remoteness of where they were last seen.
Gillam is known for thick bush and swamps, and has one main highway that leads in and out of town. Fox Lake Cree Nation, where the torched vehicle was found, is just southwest.
Upon discovery of an abandoned, burned vehicle, such as the truck found last week, police would launch a search for who may have been inside, said Brian Sauvé, co-chair of the National Police Federation, the bargaining agent for RCMP members.
“They’ll use their police dog services. They’ll use cadaver dogs, if it gets that far. This one never got that far,” he said. Dyck’s body was found about 2 km away from the vehicle.
“And they fan out, they’ll call in their tactical troop,” he said.
He said police forces also call in agencies that are trained in locating missing people. “Sometimes that involves a local search and rescue agency; sometimes it’s volunteer fire departments in smaller communities that come out and help search,” he said.
While the landscape is a challenge, Perry said there’s a good chance police can contain them.
WATCH: 2 teens considered missing, now suspects in 3 homicides in northern B.C.
“I’m going to assume the perimeter is quite large,” he said. “They will do a tactical search — grid by grid — and see if they can flush them out.”
The other options, he said, involve patience.
“Sooner or later they’re going to have to come out of the woods. They’ll have to, to survive,” he said.
“They’re going to be bug-bitten, they’re going to be cold, they’re going to be exhausted, they’re going to be starving, and sooner or later they’re going to spill out onto a roadway and the police will hopefully get that break or somebody will spot them.”
That’s one tactic, said Sauvé. Another is appealing to the community for information, through the media and social media.
In addition to the families involved and the general public, Sauvé said, thousands of off-duty police, fire and paramedics across Canada are likely to be paying attention to the case.
“It’s a lot of eyes looking for them,” he said.
WATCH: RCMP ask for help in finding two suspects in northern B.C. murders
As RCMP are now leading the case, Perry said local police departments are still crucial and should pay particular attention to petty crimes reported in their regions.
“Thefts, stolen cars, all of these kinds of things. The only way they can survive is by committing petty crimes, and we’ve seen that pattern before,” he said.
Police forces can access shared information through the Canadian Police Information Centre, Sauvé explained.
But not all of what police know becomes public knowledge. Sauve said that police withhold information for investigative reasons.
Gillam’s deputy mayor said that extra officers have been brought in to monitor the rural community and that patrolling would go all night.
The RCMP said Wednesday that a number of resources have been sent to the Gillam area. Police presence has also been increased in Fox Lake Cree Nation.
An “informational check-stop” has been set up at the intersection of Provincial Roads 280 and 290, the main road leading into the town.
WATCH: RCMP stress ‘fluid’ and ‘quick-moving’ investigation into B.C. murders
On Tuesday, officers collected surveillance footage from a store in Jade City, B.C., where McLeod and Schmegelsky stopped at some point for coffee. They also interviewed staff members.
Cpl. Julie Courchaine of the Manitoba RCMP said tips from the public continue to pour in.
The public and media’s role in the investigation is “key to the investigation,” Perry said.
“The more people that know, the more people are looking, the better the chance of having an early apprehension,” he said.
WATCH: A timeline of the northern B.C. murders