PLL 6x10 Sneak Peek: Red Cloak Mystery Person

Here's another sneak peek of the PLL summer finale 6x10.

In the  video of the first two minutes of “Game Over, Charles”, Aria thought she saw someone watching them.

In this sneak peek, the Liars try to find the person watching them.  It is someone wearing a mask and dressed in a red cloak.

Who do you think this mystery person is?   Maybe Mona?