Who is the Masked Female in the Webisode?

I looked at the photo of the girl coming out of the dressing room on the Pretty Dirty Secrets Webisode: cAll security. The girl wearing the mask, coming out of the dressing room, nods at A.

She has the same neckline/collar bone as Mrs. Marin / Melissa Hastings / Spencer Hastings. Now, we know it can’t physically be Mrs. Marin because she has reddish hair. The person standing with the mask on and big dress has brown hair. So that leaves it possible for it to be Melissa or Spencer. I don’t know who it is, but Melissa is definitely certain to be one of the As and Spencer could be as well. She could be with Toby in on the game, secretly doing it behind the liars back! Just a thought.