Deese, of North Carolina, and Fowler were found shot dead on July 15 along a highway near Liard Hot Springs, Royal Canadian Mounted Police (RCMP) said.
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Dyck, 64, was found dead on July 19 as police were investigating a car fire.
Another vehicle believed to have been used by McLeod and Schmegelsky was found in flames earlier this week, RCMP said Wednesday.
The 2011 Toyota Rav 4 that the teenage suspects were last seen driving in northern Saskatchewan was found Monday in the Gillam, Manitoba, area, authorities said.
While McLeod and Schmegelsky remain at large, police said there would be an increased police presence in the Gilliam area, with an informational checkpoint set up.
McLeod and Schmegelsky were charged Wednesday with second-degree murder in connection to Dyck's death and nationwide arrest warrants were issued in Canada.
McLeod and Schmegelsky were initially considered missing after police found their vehicle and camper on fire about 30 miles south of Dease Lake on Friday. The pair were traveling to Whitehorse in the Yukon to look for work and had not been in contact with their families for a few days, police said initially.
But on Tuesday the RCMP said the two teenagers were now suspects in at least three murders in rural British Columbia.
Dease Lake is about 300 miles from where Fowler, 23, and Deese, 24, were found shot dead. A blue Chevrolet van the couple was believed to have been traveling in was also found at the scene.
Dyck's family said in a statement released by RCMP that they were "heartbroken by the sudden and tragic loss of Len" and asked that the media respect their privacy.
"He was a loving husband and father," the statement said. "His death has created unthinkable grief and we are struggling to understand what has happened."
Deese's brother, British, told NBC News that the couple met while his sister was working at a hostel in Croatia and that they were both experienced travelers.
"It really must of been something to catch them off guard and some form of just terrible evil that should not exist in this world," he said. "I just hope they get caught and I hope this never happens to anyone else like this."
RCMP asked for the public to come forward with any tips but warned to keep a distance from the teens as McLeod and Schmegelsky should be considered dangerous.
Doha Madani is a breaking news reporter for NBC News.
Minyvonne Burke is a breaking news reporter for NBC News.