Credit: ABC Family

The Pretty Little Liars Season 4 summer season left its audience knowing more than the Liars do. We saw Ezra in "A"'s lair, so know that he's suspicious — but when will the Liars catch on the the fact that everyone's favorite teacher might be up to no good?

Spoilers suggest that one of the girls other than Aria will catch on pretty quickly — but which one? While we can't see the future, we've watched this show for long enough to have some guesses about where it's going, so we've ranked the Liars in the order of likelihood of finding out first, from least to most likey.

Spencer. Spencer seems like the obvious choice, since she's an uber-detective, but we actually think she's the least likely of the Liars for the writers to pick for this task. Why? Well, one, it's almost too obvious. Two, she was the one who found out about Toby first. Sure, this is different because Ezra's not her boyfriend, but we think it's time for a different Liar to get onto an "A" suspicion train early. That said, Spencer figuring it out first would be interesting, especially since she has seemingly wrongly accused others Liars' loves in the past.

Emily. Emily has been doing a lot of detecting of her own lately, and she also had that plot where she was working with Ezra on her college application. It's possible she will continue to meet with him, and discover something suspicious during one of those meetings.

Hanna. To us, Hanna is the most obvious choice. With Caleb headed off to spin-off Ravenswood, Hanna is going to need something to do other than mope over her boyfriend. Plus, she's the one who stole some sort of journal from "A"'s lair, so it would make sense that she gets suspicious after reading that.

Which Liar do you think will find out first? Sound off in the comments below.

Find more Pretty Little Liars spoilers here.

Catch the Pretty Little Liars Season 4 Halloween special on Tuesday, October 22, 2013 at 8 p.m. ET/PT on ABC Family.

Rebecca Martin is an Associate Editor at Wetpaint Entertainment and our resident Game of Thrones, Breaking Bad, and genre TV expert. Follow her on Twitter and Google+!