___________________________________ okay. so i read this thing on a site and it said that alison's twin sister is 'A', like they kept swapping, pretending to be one alison, so the twin knew everyones secrets, and then she burried alison and stalked the girls, so alisons twin is eventually the real "A"
In the books, Alison has a twin sister named Courtney who was mentally unstable. Being jealous of Alison's perfect life, she tricked her parents into sending the real Ali away to the mental institute in which she was suppose to be going to. Alison got out of the mental institute and upon arriving início she killed Courtney(who was pretending to be Ali.) so everyone thought Ali was dead when really she wasn't, she never had even befriended the girls.