I need to find a way to explain away the simultaneous quiet deaths in the night of a couple of thousand people worldwide such that (were this the only thing to happen, of course) nobody would ever think to take a second look into "why." There's nothing particularly special about them; they're in perfect health for the most part, and odds are only a few of them know another member of the group. They're distributed randomly around the globe too, so it can't be local. They just don't wake up one day.
Ideally, answers should work equally well as a cover for mass alien abduction or a secret society snuffing out dissenters or any number of other situations where someone would rather not let the true reason for the deaths get out.
Assume the actual method of the deaths is completely clean in itself; your answers can involve the planting of any kind of false evidence if required.