Lesli Stone is shady as hell. Per Mona, we know she's a little unhinged, and she's not too happy with our Liars. Could she have finally snapped and turned to the dark side? Was she there all along?
She was in Radley at the same time as Charles. If Charles is really the person in the black hoodie, it would not be a long shot at all for Lesli to be in the Red Coat, commiserating with "A."
This season, Lesli has a run-in with the girls at The Brew, and she says something along the lines of, "I believe in payback, too." That's some pretty damning evidence, guys.
Why She's Not Red Coat:
Too obvious. Lesli sticks out like a sore thumb as both an "A" candidate and a Red Coat candidate. When it comes to this show, such an easy connection is, more often than not, a red herring.
While it does seem that Lesli is tied up in this whole mess, she didn't actually appear until recently, and Red Coat has been around a lot longer.
Lesli claims she doesn't really know Charles. If this is true, then maybe she really isn't involved after all. Maybe she's just the victim of unfortunate circumstances.