I'm not familiar with Washington State at all, but what are the chances these two fugitives made it into Canada before it was even realized that the couple had been harmed ? I mean sure, after a manhunt began LE would have notified border security to be on the lookout for the red car, but they didn't know for sure what happened to this couple up until just a couple of days ago. Pat and Monique were reported missing almost a full week ago, which would have given the Reed brothers plenty of time to make their way out of the country before LE was able to piece things together. Shunns brother was proclaiming from the very beginning that one of their neighbors was missing and held the answers to their disappearance. I don't know how seriously law enforcement took that, but I know there were a few people in this forum that were poo-poo'ing the entire idea.
I'm not saying that these two isolationist couldn't have gone out into the wilderness, camouflaged the car, and started leading the life of mountain men. However, if one was to decide that it was time to go live off the land and pretend to be Grizzly Adams, you would need plenty of gear, shelter, fuel, and camping supplies in order to do it for very long. I really can't see them getting all of the required necessities into a 2-door Volkswagen coupe, not to mention the need for items such as ATV's and snowmobiles.
Since these murders appear to be somewhat premeditated, I have to assume that their escape was premeditated as well. "After we kill these two and hide their cars, this is where we're gonna go"..........
If they did make it across the border, would the Canadian government ship them back pretty readily or would they make it a big hassle ?