I KNOW WHO A IN PRETTY LITTLE LIARS IS !!!?

Mona is A . Allison has a phsyco twin who escaped out of a mental hospital and pretended to be allison . When they came looking for the phsyco twin , they accidentaly took allison . The night " allison " gets killed , allison kills her twin sister and buries her . Then mona steals allisons diary with all the girls secrets in it and becomes A . Later , spencer finds out ( which i think is in the next episode today , mona tries to push her off a cliff , but she falls instead , then allison becomes A . Your just gonna have to watch to hear the rest (;