Two teenagers suspected of murdering three people in northern Canada — including Australian Lucas Fowler and his American girlfriend — have been spotted more than 2,000 kilometres from where they first went "missing".

Key points: Kam McLeod, 19, and Bryer Schmegelsky, 18, have been missing since July 19

Kam McLeod, 19, and Bryer Schmegelsky, 18, have been missing since July 19 Their car was found in flames about 500 kilometres away from where Mr Fowler and Ms Deese were found dead

Their car was found in flames about 500 kilometres away from where Mr Fowler and Ms Deese were found dead Canadian police said the public should "consider them dangerous"

Kam McLeod, 19, and Bryer Schmegelsky, 18, were this morning revealed as suspects in the shooting deaths of Sydney man Lucas Fowler, 23, and Chynna Deese, 24, as well as a third unidentified man.

Royal Canadian Mounted Police (RCMP) this morning said the pair had been seen leaving the province of British Columbia and were spotted in northern Saskatchewan.

However, in a subsequent alert, police in Manitoba said the teens had been spotted in the town of Gillam — three provinces away from where Mr Fowler and Ms Deese's bodies were found.

"We have reason to believe they were recently in the Gillam area," an RCMP statement said

"[They] are considered dangerous. If you spot them — take no action, do not approach."

Mr Fowler — son of NSW Police Chief Inspector Stephen Fowler — and Ms Deese were found shot dead on July 15 on a highway in northern British Columbia, 20 kilometres from Liard Hot Springs.

Mr McLeod and his childhood friend Mr Schmegelsky were reported missing on July 19.

Their pickup truck was found on fire at a highway stopping point in an area known as Dease Lake in British Columbia (BC), about 500 kilometres from where the young backpackers were found.

Australian man Lucas Fowler and girlfriend Chynna Deese were found dead in northern British Columbia. ( Supplied: NSW Police )

A body, which has not yet been identified by police, was found around 2 kilometres from the scene.

'Victims' turned suspects

It was first feared the missing teenagers had been the victims of a crime, but in a dramatic twist RCMP spokeswoman, Sergeant Janelle Shoihet, released photos of the pair taken in Meadow Lake at the weekend.

"Given these latest developments, Kam and Bryer are no longer considered missing," she said.

"The RCMP are now considering [them] as suspects in the Dease Lake suspicious death and the double homicide of Lucas Fowler and Chynna Deese."

Loading

"Thanks to the public yesterday ... we have new information where we've confirmed they were seen in northern BC, we've been able to confirm that information in last 24 hours," Sergeant Shoihet said.

"I've been receiving new information — honestly before I just stepped on this stage — new information is still coming in."

She said the pair were seen driving a grey 2011 Toyota RAV4, but warned they could have since changed their appearance and their vehicle.

Mr McLeod and Mr Schmegelsky were childhood friends and it was believed they were travelling through the area looking for work before they disappeared, the RCMP said.

"Kam and Bryer have periodically connected with family and friends over the past week and it is possible that they are now in an area without [mobile phone] coverage," a spokesperson had said, before the pair became suspects.

A sketch of an unidentified man found dead near the teens' car. ( Supplied: RCMP )

Yesterday, Sergeant Shoihet said it was "unusual to have two major investigations undergoing of this nature in northern BC at the same time", and confirmed police were looking at potential links between the deaths of the unidentified man and the couple.

Mr Fowler's father, NSW Police Chief Inspector Stephen Fowler yesterday made an emotional plea at the press conference for any information.

His voice broke as he described how his son and Ms Deese were "inseparable".

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 21 seconds 21 s CCTV footage shows couple embracing at Canadian petrol station days before murder.

"As you know, I may have been an experienced police officer but today I'm standing here as the father of a murder victim," he said.

"It's a love story that's ended tragically. It really is," he said.

"It's the worst-ever love story."

Police have also released a sketch of a man said to be one of the last people to speak to Mr Fowler on Highway 97 on the evening of July 14.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 1 minute 50 seconds 1 m 50 s Lucas's father, Stephen Fowler, has described how "distraught" the family are

He was described as Caucasian, with darker skin and dark hair, with a possible beard or glasses.

He was driving an older model Jeep Cherokee with a black stripe on the hood and a black bullbar and is believed to have been travelling south.

Sergeant Shoihet said he was not a suspect, but someone police wished to speak to.