WARNING!!! IF YOU ARE NOT UP TO DATE WITH SEASON SIX PLEASE DONT READ THIS AS IT MAY CAUSE SPOILERS!!!
As usual I am going to start with her name. Sara is the name of the author of the book which could connect her to ‘A’ as the author was the one that created the whole story and by giving ‘A’ the name of the author could be a tribute to her. As for her first name there is nothing else connecting her to ‘A’. Harvey however means warrior. Now, we all now that Sara is a warrior for surviving the doll house, however, her last name also means eager for battle which could mean that she wants to torture the liars because she wants a battle but doesn’t want to get hurt by the liars so she’s the only one who can win.
Now I mentioned this in my Byron Montgomery theory that Charles has to be roughly 5’7 or 5’8 as Spencer is 5’7 and Charles is roughly the same height. Sara is 5’8 which makes her the perfect height as Charles looks just a little taller than Spencer.
When Sara is recovered from the Dollhouse she is in hospital and we never see her parents and they have never been given a name. Could this be because they will try and keep her in the house instead of letting her go out because they are scared of what might happen if they let her out. By not going home and living with Emily this means that Sara can still hide in plain sight and torture the liars.
When Sara is in hospital Emily goes and visits her as they are all in the same hospital. Emily asks Sara how she got put in the dollhouse. Sara replies by saying that she hit her head or someone hit her. This is very similar to the way Ali went missing as she got hit in the head and then buried alive. Sara could have said this because she is ‘A’ and because of this she knows everything about everyone.
In the episode ‘She’s No Angel’ we see Sara talking on the phone to her ‘mother’ when Emily enters Sara says that she can’t understand her because she is drunk and hangs up. However if you had been locked underground wouldn’t you want to talk to your parents? I think it is strange how the minute Emily enters Sara hangs up. I think that she was on the phone to her minions or others on the ‘A’ team so that they could plan what they were going to do next and so that Sara can keep them updated on Emily.
In the same episode we see Sara and Emily get a tattoo each. Whilst Emily is having her tattoo done she gets a text from Aria and Sara see’s. When Sara see’s the text she suddenly goes really anxious, shocked and upset. She then looks around the room and gulps. This could be because she thinks that she has been discovered. When Emily tries and explains the text Sara gets angry and runs off, Emily runs after her. They soon reach a brick wall and talk, however they soon see a hooded figure and run off. This is what Sara could have been on the phone about earlier on in the episode, she could have planned everything out. Because as we know ‘A’ is very smart.
Lastly Varjak’s number spells out Sara Harvey. This is a clue because Cyrus ends up in hospital because of Varjak. When the liars go and speak to him they ask him who done this and Cyrus says Varjak. We still don’t know who Varjak is but I think this is a very important piece of information as Sara could be going by the name Varjak as well as Charles just to confuse people.