The girls are closer than ever to unmasking “A” on “Pretty Little Liars.” The only catch is that they need proof of their main suspect – Lesli (Elizabeth McLaughlin).

After finding Mona (Janel Parrish) at Radley with Lesli’s old files, Spencer (Troian Bellisario) and Hanna (Ashley Benson) break the news to their other girls in episode 6. While it’s pretty suspicious that Lesli was in Radley at the same time as Mona, Charles DiLaurentis and Bethany Young, the others still have their doubts. The only way to stop worrying about “A”? Do some digging.

While Sara (Dre Davis) goes off to work with Caleb (Tyler Blackburn), Emily (Shay Mitchell) takes off to meet up with Aria (Lucy Hale) at the junkyard where she took the picture of “A.” But before Emily can get there she runs into a distressed-looking Mr. DiLaurentis (Jim Abele). He discovered a “Happy Birthday” card on his car and after reading the contents inside wants to know who put it there. Unfortunately, Emily doesn’t know.

Meanwhile, Hanna is waiting on Spencer so they can break into Lesli’s car to look for clues. When Spencer gets distracted by a visit from her old sober coach, Dean (Nathaniel Buzolic), Hanna takes it upon herself to “borrow” Lesli’s car. She somehow manages to convince the valet attendant to give her the keys – and the risk of getting caught was well worth it.

When Spencer arrives, the pair discover Lesli’s work badge for the college lab she works in. And that’s not all. She has a whole box of fake glasses and four cages big enough to house four teens. Dun dun dun …

As Hanna and Spencer make their big discovery, Aria is having a hard time getting Emily to stop worrying over Sara. Fortunately, Ezra (Ian Harding) offers Emily a distraction. Ezra texts her to let her know that her old friend from her Haiti charity work is in town to see her.

Emily ditches Aria at the junkyard with her new photo buddy, Clark (Titus Makin Jr.). Aria’s not too pleased to be doing some sneaking around in front of him – especially when she finds a doll that looks like her with a knife in its eye.

The doll makes Aria stress over the threat of “A.” Elsewhere, Emily is stressing over Sara. Her friend asks her to take a trip to Thailand in June to help build houses. Emily wants to jump at the opportunity, but she can’t leave Sara. The solution? Bring Sara along! Unfortunately, that plan has a big flaw. For starters, Sara is still not emancipated and her mom won’t sign off on the paperwork. But another issue is that Sara is still scared for her life, believing that someone deliberately tried to hit her on her way home from work.

The roadblock with Sara forces Emily to stay in the country. Meanwhile, Caleb finally gets over his awkward shutout with Hanna. Taking some advice from her mom, Caleb decides to stop acting like Hanna is fragile -- and pulls her in for a steamy kiss (and potentially more). But the big shocker of the episode relationship wise comes from Spencer. Dean tells her that he can’t see her anymore -- because all he wants to do is grab her and kiss her! Spencer doesn’t react and Dean leaves.

Pretty Little Liars The Liars discovered that "A" had implanted chips in them in episode 6 of "Pretty Little Liars." Photo: ABC Family

The big “A” developments in episode 6 came when the girls paid a visit to Lesli’s place of work (outside of office hours). Breaking into the lab they discover that “A” had them chipped. Other than that, they make no discoveries that could tie Lesli to “A.” That’s when Mona shows up. She reveals that she followed them to Lesli’s work lab in order to save them from getting caught by the campus police. When the Liars begin to grill her about Lesli’s connection to Charles, Mona comes clean about everything.

According to Mona, Lesli HATED Bethany and is NOT pretending to be Charles. She’s simply “pretending to be stable.” Lesli told Mona that she only heard the name Charles DiLaurentis once, and that it was the night she sneaked out – the same night that Alison was “killed.” Supposedly Lesli and Charles broke out of Radley on the same night – which means that Charles was really alive at the same.

But what about the paperwork that says Charles died years prior? When Mona looks it over she reveals that the form is a sham. There is no way that Charles would have been an eligible donor with the medication he was on.

The Liars are not the only ones who find out in episode 6 that Charles is alive. “Pretty Little Liars” fans find him digging up Charles’ grave. Turns out that the note Mr. DiLaurentis got on his car was from his estranged son.

“Dear Daddy, Coming home for my birthday. You should plan a party to die for. Just you. Love, Charles.”