There have been a lot of twists and turns on Pretty Little Liars, but this theory may just be the biggest possible twist of all. On the latest episode, it was (finally!) revealed who killed Jessica DiLaurentis. According to Peter Hastings, Mary Drake was the culprit but naturally fans are still a bit skeptical for many reasons — one of which is that many people believe Jessica is actually still alive and pretending to be her sister. So is Mary Drake really Jessica DiLaurentis on Pretty Little Liars?
Well the first clue that fans may be right is the fact that Andrea Parker, who plays Mary Drake and Mrs. D., told TVGuide that "Peter lies like a rug," and "there will be more revealed about what happened the night that Jessica was murdered." This basically seems to confirm what fans already knew (that Mary is the one who's dead, not Jessica), but still it's good to know that fans are potentially on the right hunch.
The biggest reason fans are suspicious of Mary Drake actually being Mrs. D is because of Peter's flashback in the last episode. In the flashback, Mary Drake, dressed as Jessica, paid Spencer a visit after Spencer got out of rehab. Peter stopped her as she tried to sneak out of the house and at first thought Mary was Jessica and was surprised to discover she was Mary.
This has spawned a variety of theories, though they all suggest the same thing. Reddit user lyoushe suggests that really was Jessica talking to Peter, she just wanted him to think it was Mary for whatever reason. Jessica then killed Mary, who was disguised as Jessica, and took on the identity of Mary Drake.
The more popular theory, however, is that Mary Drake did impersonate Jessica that night and the real Jessica killed her and assumed her identity. This theory was brought to life because Mary Drake's outfit looked a bit similar to the one "Jessica" was wearing when she died, however, after closer examination it may not be the exact same outfit, though it's arguably pretty close. Maybe this is to throw us off the scent?
Even so, most fans are certain that Mary Drake is actually Mrs. D and Reddit user covermaker provides even more substantial evidence — pointing out how in the first half of Season 7 both Ali and Jason caught Mary Drake doing things their mother often did like singing the same lullaby and cooking the same kind of meals. Covermaker also suggests that Jessica (as Mary Drake) purposefully told Spencer that Mary Drake was her mother not because she cared but because of the drama that then ensued.
It definitely looks like the fans are on to something. Thankfully, they won't have to wait too much longer before all is finally revealed.