Credit: ABC Family

Pretty Little Liars Season 4, Episode 5: “Gamma Zeta Die” revealed what seemed like a major clue in the pursuit to discover what Ali was up to the summer of her (maybe) death. That strange room Spencer found in the Cicero College sorority house was beyond creepy. Who could have been staying in it and answering Ali’s calls?

Cece

Raise your hand if you can imagine Cece hanging out at that sorority house. Wren told us last season that Ali got Cece kicked out of college because of an incident at a party. Could Cece have been staying in that room to evade campus authorities while still finding the time to sip margaritas with her house sisters? It’s hard to imagine Cece enduring that frankly abysmal level of home decor, but maybe the sisters have repurposed the room since Cece’s time there? If it was Cece who stayed in the room, why was Ali calling her? You’d think Cece would have been a bit pissed about the whole “getting kicked out of college” thing. On the other hand, backstabbing and sabotage was probably par for the course with these two friends, and days spent with only a retro radio for company probably get dull.

Mrs. Grunwald

Who is the mysterious Mrs. Grunwald, and could she have known Ali? We were surprised to hear Mrs. G.’s name brought up because she is going to be associated with Ravenswood. Is her mention just a Ravenswood red herring, or could the former sorority mother have been in touch the summer of Ali’s death? Spencer certainly seems to think Mrs. Gruwald was the person Ali was calling. In a sneak peek for next week’s episode (Season 4, Episode 6: “Under the Gun”), Spence details her theory to a pissed-off Emily: Mrs. Grunwald used to disappear for hours at a time, only to reappear out of thin air without seeming to have ever left the house. Sounds suspicious to us, but how could Ali have met the mysterious matron? And what could they have been talking about?

Ali’s Twin

Yep. We’re back on board the twin bandwagon (well, we never really hopped off). Though the PLL Powers That Be have said they are not exploring the twin storyline, we still think it’s one of the better theories out there. If Ali did have a sister, could she have been staying at the sorority house, possibly locked away in the hidden room? Spence found claw marks on the back of the door implying that someone was trapped there against their will and trying to get out. Maybe Mrs. G. was disappearing to this room, not for a little alone time, but to check on Ali’s twin sister. It makes more sense that someone was locked in that room (would she really choose to spend free time there?) and, if that’s the case, Ali’s twin is our number one suspect. Could Ali have been calling her sister for some heart-to-hearts?

Of course, the Beach Hottie is also a possibility, but that seems like a weird place for him to go for a little chat.

Who do you think Ali was calling? Share your theories in the comments below!

Catch the next episode of Pretty Little Liars on Tuesday, July 16, 2013 at 8 p.m. ET/PT on ABC Family.