There's always been something, shall we say, off about Lucas, but he's been acting particularly shifty-eyed upon his (suspiciously timed) return to Rosewood. That, coupled with his pre-existing obsession with Hanna, puts him atop our list of suspects.
Given that we're only two episodes into Season 7 and Elliott is already going rogue, it wouldn't be too surprising to learn he's also forged a textual identity of his own. Plus, Elliott and A.D. share the same goal: to completely and utterly destroy Charlotte's supposed killer.
We already know that Jason is returning to Rosewood in Season 7, and you have to admit: His absence these past few weeks has been beyond conspicuous. Plus, I can’t imagine a greater surprise for PLL fans than to discover Jason isn’t the beautiful dumb-dumb we’ve taken him for all these years.
This one would be pretty surprising, if only because of how much pain A.D. has directly inflicted upon Alison. But then again, would it be that surprising? Not only does Ali share initials with the show's new mystery villain, but she also has a history of monster-like behavior.
It isn't usually the most obvious person, but in this case, it just might be. (Not since Revenge‘s Victoria Grayson have we seen a woman sip tea in such a devious manner.)
A SPECIAL GHOST STAR
As a special thank-you for clicking this far into our gallery of suspects, we present our farthest-reaching theory yet: Could "A.D." stand for "after death"? Could the Liars' new tormenter be a presumed-dead character they've already mourned?