More intriguingly, she also seems to suggest the person who is calling the shots is female, saying "they" — we're pretty sure she means the Liars — "need to understand that she's in charge."
Of course, we don't have the whole scene, so it's possible that this isn't the major clue it seems to be. But assuming it does mean that the head of the "A" group is a woman, that really narrows down the options. So who might it be? Here are our favorite theories.
1. Alison. Sorry, we're not letting this one go until there is definitive proof that it couldn't be true. We still think Alison (Sasha Pieterse) might be alive, and running the whole shebang. She has the smarts and the sadistic streak needed, and, post-"death," she has all the time in the world to pull it off.
2. Alison's twin. Another favorite theory. In the books, Ali has a twin, and there have been hints that she might have one on the show, too. Maybe Ali's twin is the head of the "A" team, perhaps as some twisted way to torture her sister and her sister's friends.
3. CeCe. The girl who taught Ali her manipulative ways clearly has the skillz for some epic evil, and we know she knew many of the Liars' secrets. But why would she target Ali's friends? Unless there's more to her backstory with Ali then we know, we don't understand her motivation.
4. Melissa. Spencer's (Troian Bellisario) older sis has a twisty, complicated background with Ali, the NAT club, and the Liars. And while she doesn't quite seem like a criminal mastermind, she is a Hastings. They can do anything if they put their mind to it.
5. Jenna. We're leaning towards thinking Jenna (Tammin Sursok) isn't as evil as she once seemed, but we should never discount her. Girl is hella smart, and she has a real reason to hate the Liars.
Who do you think it is? Share your theories in the comments below.