The Liars may have unearthed their biggest clue about “A” yet, and it’s all thanks to Aria’s (Lucy Hale) new photography friend, Clark (Titus Makin Jr.). The latest reveal came during episode 5 of Season 6, “She’s No Angel.”

Like the previous weeks, the girls were struggling to return to normal. But with “A”/ Charles DiLaurentis still on the loose, that was proving to be a difficult task.

Spencer (Troian Bellisario) initially resorted to weed cookies in order to calm her nerves, however a run-in with her old sobriety coach, Dean (Nathaniel Buzolic), led her to give up the goods before she got hooked. Emily (Shay Mitchell) focused all her time on helping Sara (Dre Davis) recover from the Dollhouse – including working with her to get emancipated and getting a tattoo. Meanwhile, Aria let herself get consumed by photography, as Hanna (Ashley Benson) decided to put all her efforts into finding a way to get inside Radley to find out more information on Charles.

Aria’s photography ultimately led her to find the biggest clue about “A” – their tormentor might be a girl. The teen made the latest discovery while helping Clark develop his film from their trip to the junkyard. Clark took a photo of an old fan … and in the background is a hooded figure. While a face can’t be seen, it’s clear that the mysterious person has a bust.

That was a big reveal – but the Liars found out another shocker at the end of episode 5. Mona (Janel Parrish) reappeared for the first time since they made it out of the Dollhouse. And while Hanna was happy to see her old friend, one person was definitely not – Lesli (Elizabeth McLaughlin). “Pretty Little Liars” fans will remember that Lesli was Mona’s childhood friend who surfaced after Mona was “murdered.” It was thanks to Lesli’s testimony that the Liars got put away for her murder. She ran into Mona at the coffee shop and the exchange was TENSE. Turns out that Lesli was being questioned by the police, who believed that she helped Mona fake her death. Lesli vowed to payback Mona for everything she did to her.

Hanna initially thought that Lesli was being overdramatic … until she found out that Lesli was in Radley at the same time as Mona and Charles.

Hanna and Spencer made the discovery while they were snooping around Radley. They discovered one of Charles DiLaurentis’ old files, which confirmed that he was dead. How could they know for certain though? The file contained a work order stating that his organs – heart, liver and kidney – were donated after his death.

The two were about to leave when they heard a noise coming from another room. When they opened the door they were shocked to find Mona inside.

Mona was clutching Lesli’s file. According to the paperwork she was in there for years … and was roommates with Bethany Young, the dead girl who was mistaken for Alison.

Mona claimed that she was stealing the file to repair her friendship with Lesli. But there is more to the story than what she was telling the girls. “Pretty Little Liars” later see Mona making a phone call to Lesli after Spencer and Hanna took the file. “They know,” she tells Lesli. And Lesli is NOT happy. “You always screw everything up,” she yells at Mona, freaking out.

What do you think of the latest “A”/ Charles DiLaurentis reveal on “Pretty Little Liars”? Tweet your thoughts to @AmandaTVScoop.