I think the EQ may have something to do with it, just to frame MM, but I can’t help but wonder if mr. Gold didn’t plant it in the episode “the heart is a lonely hunter”, where he was in the woods with a shovel gardening. I have other theories about that scene as well. None the less, I think he secretly wants the curse broken and in order to do that, he has to make Emma dig deeper to reveal the FTL. Just a thought.
Gold E. Locks
The heart definitely said EQ to me and I can totally see Regina doing the frame-up of MM. They said it was a human heart but I bet their testing comes back inconclusive as to whose it is. Would killing Kathryn really suit Regina’s purposes? Maybe she figures it will make David hate MM, which it probably will if he believes it.