Read spoilers at your own risk! For more on Wetpaint Entertainment's philosophy on spoilers, click here.
In the sneak peek, we see someone being loaded into an ambulance whileHanna (Ashley Benson) sobs. Then we see a policeman questionEmily (Shay Mitchell), asking "the deceased was a friend of yours?" and "I'm trying to understand what happened. Did you know the victim?" which seems to confirm that there is another death after all. A second body is rolled by as they talk, and Emily says she DOES know "the deceased."
So, who dies? We're as in the dark as you guys, but here's what we can deduce from other spoilers, pictures, and speculation.
Is it a fight? Based on the fact that it looks like there are two bodies, we think there's probably a fight that leaves one person injured and the other dead. While Hanna seems very upset in the sneak peek, we actually think it's more likely that she's upset over the injured person.
Are the Pretty Dirty Secret stars safe? A lot of potential victims seem to be safe by dint of being in the new Pretty Little Liars web spin-off, Pretty Dirty Secrets. It sounds like Pretty Dirty Secrets takes place in between the summer finale and the Halloween episode. If that's true, than the characters featured on it probably live, right?
It's probably not family. By the same logic, we suspect the Liars' parents are okay (though Hanna's mom could be the person who's hurt). The same goes for Melissa Hastings (Torrey DeVitto). She and Spencer might have a troubled relationship, but Spencer would be way more upset if her sis died.
That leaves... That doesn't actually leave a whole heck of a lot of characters. But there are three people who we think are at high risk. And they are:
Nate. Nate is actually our number one guess for now. We could totally see him attacking Emily and/or Paige out of jealousy. Maybe someone close to Hanna (probably Caleb, maybe Mona) jumps in to help. This would also explain Emily's hesitancy when asked if the deceased was her friend, since her relationship with Nate is very complicated.
Mona. While it sounds like Mona will still play role in the winter season, that doesn't rule out her dying here — after all, Alison (Sasha Pieterse) has been dead all along, and that hasn't stopped her from being a major figure in the story. This would explain why Hanna is so upset while the other Liars aren't, and obviously we wouldn't put it beyond Mona to attack someone. Plus, we do know her role in the finale is "unforgettable," and it looks like she might get out of Radley, so...
Jenna. We don't really think the writers would kill off such an intriguing character, but she is always messing around where she doesn't belong, so we can't rule her out.
Could it be Ali's body? Our final theory is that the "deceased" here is actually Alison, again. If that's the case, maybe someone was injured fighting "A" in his/her lair, where s/he was keeping Ali's body.