Episode 20 of “Pretty Little Liars” ended with a major jaw dropper. After months of fans believing that Ezra has been torturing Aria, Spencer, Emily and Hanna as “A,” the ABC Family series through in a serious twist … Ezra isn’t “A”!

Despite the fact that Rosewood High School English teacher is “Board Shorts” and has been spying on the four teens with a mega-computer, he’s supposedly innocent of trying to kill Alison. But if he’s not the one causing problems for everyone – who is? Eliminating Mona, CeCe, Toby and Shana from the equation, there are five main “A” suspects:

Jackie – Don’t remember Jackie? She was in the picture in season 2 and played a huge role as Ezra’s ex-fiancé. Did Alison break up Jackie and Ezra? Ezra just revealed that he was seeing Alison while he was in college and because of this Jackie could potentially want revenge against Alison and her friends. And while the motive is there, it’s important to note that “A” forced Aria to blackmail Jackie about her plagiarized thesis paper.

Melissa – Melissa has been missing in action for a while (supposedly at an internship in London), however fans can’t forget her involvement as the Queen of Hearts and Black Swan. Spencer’s sister claimed she was being blackmailed by Wilden and that she’s been trying to protect Spencer since before “it” all started.

Wren – Dr. Wren might be able to melt your heart with his smile, but he’s also got a dark secret. He seemingly knows about red coat, has hit on both Spencer and Hanna, and is supposedly living with Melissa again. However the real suspicions surrounding Wren come from his involvement at Radley. “Pretty Little Liars” viewers will remember that season 3 revealed that Wren’s work at the mental institution connected him to Mona, CeCe and Ali. Fans also can’t forget that he has a seriously strained relationship with a Radley orderly, Eddie Lamb.

Jason DiLaurentis – Alison’s half-brother has been a suspect on and off for the past four seasons. His history of drug abuse, jealousy of Alison and relationships with Ian, Garrett and CeCe all point towards him being “A.” Jason has supposedly been out of the state at his grandparent’s house, and an episode in season 4 revealed that he “fell off the wagon.”

The Alison Twin Theory – “Pretty Little Liars” fans hope that “A” is a character that they already met – but what if “A” isn’t? A theory based off the novels has viewers speculating that Alison is being chased by her twin.

Who do you think is “A” now that Ezra has cleared his name? Let us know your thoughts in the comments section or send a tweet to @AmandaTVScoop.