Mona was A in season 2. She was the one messing around with the dolls, and sending some texts. But then the liars got a text saying how there was another A who had been dealing with the dead bodies. At the moment it is sort of believed to be Ezra, however it hasn't been confirmed but all the evidence points to him at the moment.
Nobody knows. Different characters helped A, such as Mona, and Spencer's boyfriend Toby right now they think Ezra , Arias boyfriend is A because he's been stalking the girls. The one who truely knows is Ali.
I am on series 2 but I have heard there are a few A's
At the end of series one we are lead to believe Ian is A or Jenna
In series 2, The cop, Jenna, Ian, Melissa and Mona are 'A' (a team)
I have heard that Ezra is A in the upcoming series. I think Ezra is the main one!
In season 2 it's revealed Mona is A with Toby's help. As far as season 4 we still don't know. My guess is Aria.
The tv show not the book.
