Ken Albertsen had just driven 15 hours in one day.

Returning to his home in Alaska from a family trip to Montana last July, the 54-year-old pulled over to the side of the Alaska Highway in Yukon, about 100 kilometres north of the border with B.C.

Albertsen was getting ready to close his eyes when a pickup slowly passed and stopped a little farther up the road. A tall, skinny man got out. He appeared to be holding a long gun.

To Albertsen's unease, the truck started to pull away and the man walked toward the trees, where he assumed a hunting position and slowly began approaching his vehicle.

As the gunman neared, the same pickup truck returned and began slowly blocking Albertsen's exit.

"At that point I realized that this feels like an ambush," Albertsen told CBC News.

WATCH | Ken Albertsen recounts his close call

Man escapes after encounter with fugitives 1:38

"There's a guy approaching the back of my vehicle with a long gun, there's someone pulling around in the front. If I don't take action immediately, I'm going to get blocked in."

Albertsen, a photographer who lives in Palmer, Alaska, is a key witness named in recently unsealed court documents detailing last summer's Canada-wide manhunt for admitted killers Kam McLeod and Bryer Schmegelsky.

The RCMP documents, obtained by CBC News, describe the injuries of the three victims, items found at crime scenes and behind-the-scenes details of cross-agency efforts to bring the two young men to justice.

The bodies of McLeod, 19, and Schmegelsky, who would have turned 19 on Aug. 4, were discovered on Aug. 7 near the Nelson River in northern Manitoba.

RCMP found the pair after an intense 15-day search which began with the seemingly random killings of Australian Lucas Fowler, American Chynna Deese and University of British Columbia lecturer Leonard Dyck.

Fowler and Deese were shot on July 14 or 15 at the side of the Alaska Highway near Liard Hot Springs in northern B.C. Dyck's body was found four days later in a highway pullout near Dease Lake, about 500 kilometres to the southwest.

McLeod and Schmegelsky admitted responsibility for the three killings in videos left behind on a digital camera, police say.

'Stalking behaviour'

But on the night of July 17, Albertsen had no idea the two young men from Port Alberni, B.C., had started a killing spree on remote sections of highways in the north of the province.

It was just before midnight, dusk on a midsummer evening. The light was disappearing but Albertsen had good visibility from the pullout where he had parked perpendicular to the highway, facing the road, to get some sleep.

He had just crawled into the backseat and taken his jeans off to lie down, when he saw the pickup pulling in. The vehicle slowed down, slower than walking speed.

The bodies of tourists Chynna Deese and Lucas Fowler, left, were found near Liard Hot Springs, B.C., on July 15. Leonard Dyck, right, was found dead four days later near Dease Lake. (New South Wales Police; University of British Columbia)

Two men were inside; police would later confirm that Albertsen's descriptions of them matched those of McLeod and Schmegelsky.

Albertsen says the passenger door of the pickup truck opened to let out the man with the gun.

He remembers thinking it was strange to see the vehicle pull away after letting the passenger out.

The gunman then crept toward the treeline in a way Albertsen and court documents describe as "stalking behaviour'"or a "hunting stance."

He then walked slowly from tree to tree toward Albertsen's vehicle, holding the rifle or shotgun in "a low-ready position."

"His left hand is on the forearm of the gun, his right hand is on the stock close to the trigger. He's carrying the long gun in a position that would enable him to wing it up and use it readily," said Albertsen.

"By this point I'm paying attention, I don't know I'm under threat, but I'm paying attention."

Ken Albertsen was driving this truck when he pulled over to sleep. He was just getting ready to close his eyes when a pickup passed, slowed and stopped in the same pullout. (Submitted by Ken Albertsen)

'Protected by God'

When the truck returned and pulled into an angle that would cut him off, Albertsen says he knew he had to act.

"I leaped over the backseat, in my underwear, started up the truck, put it in gear and roared out of there," he said.

Albertsen says he tried to look at the man behind the wheel but the driver covered his face as he sped by.

He drove another three or four hours, full of adrenaline after the encounter.

"I honestly believe I was protected by God," he said.

Albertsen admits he hadn't listened to the news for a few days but after returning to Alaska and seeing local news reports about a Canada-wide manhunt, he called the RCMP.

By this stage, McLeod and Schmegelsky had also killed 64-year-old Dyck.

Albertsen made a statement to the RCMP on July 21. On July 23, the RCMP named the pair as suspects.

Months after that midsummer night, Albertsen finds it difficult to pass through the area. He thinks about the victims and how close he came.

"I've been in different dangerous situations at various points in life," he says.

"But realizing that you may have actually been targeted by someone meaning ill will — it's sobering."