Sorry Ovid, but badguy
CAN'T steal the gold. It's not possible with your rule set:
steals(PERP, STUFF) :-
or in English:
* And the person doesn't know the person who owns the stuff they might steal.
On the other hand the badguy can steal your rubies:
X = rubies
and so can merlyn but only if we're allowed to add one more fact:
I think you might want to meet merlyn really fast, and maybe get him to introduce you to badguy. :)
Update: Oops. Forgot that the PERP had to be a thief in order to be able to steal. Which would have meant that merlyn couldn't have stolen the rubies and I would have appeared to not have known what I was talking about. :) I've fixed this now of course.