The New "A" IS AN ANONYMOUS CHARACTER THAT SENDS THREATS To Aria , Emily , Hanna And Spencer. and tricked Emily into going to Alison's grave to make it look like Emily dug up her grave which Emily doesn't remember doing. i think the new a killed Maya because she find something that belonged to Alison that connected to her killer.The New A is more dangerous than Mona this is proven when "A" sends Emily a necklace with human teeth. and when "A" unzipped a body bag that she's been hidden in a frozen that belongs to Ali. I believe the new a to be Jenna because she wears red ... so does the new a . and she was driving Emily the night Alison's body was stolen and she had a gold mask on her screen visor. and she can see she's not really blind. and another reason why believe Jenna's the new a is she met someone in the park and told them that the PLLs were going to be at the masquerade ball and she said " You know what you need to do ". and handed the stranger something wrapped in a box which could have been the gun Mona stole from Mr. hasting's desk. and at the end of the season 2 finale Mona Gets a visitor from someone wearing the Vivian dark bloom coat. and Mona said to Jenna or Ali " i did everything you told me too "
and P.S. Jenna was at the masquerade ball and followed Aria to meet Ezra and took off her mask. so that means Mona and Jenna were both UnmAsked at the masquerade ball and that makes them both members of The A-Team.