Now what should the OP do in this case?

Call the police! Or, relax a bit. :-)

More seriously, while I consider it as not very likely that things will be 'stolen' in this way, this is perhaps besides the point. So, possibly, the following information is of some use to you:

These deletes on MO are "soft" deletes. The question and all that goes with it are not truly/fully deleted. "Deletion" on MO (at least the one we are talking about here) merely means that in some database the item is marked as "delted", which in turn means that it is displayed differently to those browsing the site (where "differently" means "not at all" for most users). But it can always be recreated if needed. So, if ever you should need to establish your priority on some idea via an MO question, you could, if this eventually arises, then ask for an undeletion. [In general I consider this first as a bit unlikely, and second MO not as the place to establish priority on your ideas. But, well, this is perhaps besides the point.]

And certainly except in these cases we should wait much longer than the 4-day minimum to do it.

I should perhaps add/explain that it was not my intent to suggest some 'conspiracy' against dr, yet only to point out that (likely) dr is/was not just talking about a single deleted question, as suggested by the first reply, but a sequence of such events (possibly all noted at once or in somewhat rapid succession).

This is a bit unusual; in particular if ever (I cannot know) all were deleted at about the same time.

So to follow up on geraldedgar it seems to me the question of dr is why the account was essentially completely eliminated.

ADDED: In view of the dates geraldedgar provided later, I am now unsure whether I remember this right; there definitely was a question like this by I quite strongly believe dr; but there was also another more recent one by dr, I think, asking about the result specifically. (It seems also gone.) I might have mixed up the two.