Going by the stories told by the First Nations peoples of these creatures snatching women and children and considering the Missing 411 cases I would say that it probably happens from time to time. These are large, highly attuned omnivores that are physically capable of snatching a person if the scenario and conditions were right. If food was scarce or if the said Squatch was either old, sick, or injured a predation could definitely happen.
If you look at a decent chunk of the Missing 411 cases the victim is usually found miles and miles from the point of disappearance and usually they are found (if they were found at all) through miles of highly rugged and sometimes unnavigable terrain (mountain ranges, swamps, thick forests, across rivers, ect). Interestingly enough, a sizable amount of the disappearances happen just as or before a very nasty weather system moved through the area, delaying any search and rescue efforts by a couple of days, if not longer. If you ask any accomplished hunter or fisherman about bagging that monster buck or that trophy fish, they'll tell you that the conditions need to be on point in order to optimize the chances of your pursuit being successful (environment/habitat, tracks, sign, game trails, wind, weather patterns, air and water temperatures, tides, season/time of year, ect). And it seems that the optimized conditions and scenario for a Sasquatch predation would be on a lone, unarmed hiker along a desolate trail surrounded by miles and miles of harsh terrain and just before a nasty front or weather system goes through the area.
Another thing that I think that gets overlooked is that the Squatch in question might not necessarily need to be old, sick, or injured to predate on a human. Just as we have "rogues" amongst humanity that buck societal norms or out right violate them (killers, criminals, gangsters, psychopaths, sociopaths, cults, cannibals, ect) I would imagine that Sasquatch might have those issues as well. The "rogues" may live in regions where the more "conventional" groups and clans aren't located or don't go to. Or they may live in proximity of (or be members of) clans that are more lenient to human predation or out right allow it or encourage it. Just as different orca pods focus on hunting specific prey items (be it salmon, herring, seals, sea lions, sharks, sting rays, dolphins or whales) I would imagine different Sasquatch clans would have different attitudes on the predation of humans.
As far as concealing the remains go, I would imagine that they would take the extra step in burying the bones deep if they felt the need to. Though, there have been cases of the search and rescue dogs refusing to follow the scent trail of the victim due to being afraid of something...
Yes, it's definitely a possibility.