You raise some interesting concerns....but Seattle PI reporting this morning that it was found in a crawl space about 3' off ground, under a tarp, with boxes on top of it...apparently a couple "unusual" items next to body.
So guess it comes down to how much suspicion they had at the time of the seach as to whether it was worth tearing the place apart or if they just looked room-to-room to see if it was going to solve the "missing person" case.
Much more to be revealed today from Medical Examiner, etc. ... we'll keep you posted from up here in Seattle, or check TV sites as they are treating this as today's major story.