Because it was a secret
No because she switched places with her twin Courtney so they think that Ali is dead.
****SPOILER ALERT*****No-Alison has an identical twin sister named Courtney. Courtney always pretended to be Ali, so her parents sent Courtney to a mental institute (but by accident they sent Ali.) Courtney was pretending to be Ali in Spencer's barn. (The body found in the DiLaurentis' backyard was really Courtney-who was killed by Ali.) Ali had escaped from the mental institute and seeked revenge.No it's her twin sister that is dead! Alison is really "A"
Ali, her twin sister, killed Courtney.
it was Courtney Ali's twin sister ian raped ali(Courtney)
first off, Courtney, her twin was killed. not ali. an ali killed Courtney because she took over her life. Courtney was mentally ill and stayed in an asylum, however Courtney would always say shes ali when she wasnt. Courtney escaped and her parents couldn't tell who was who. so they sent ali instead of Courtney to the asylum. ali escaped and was mad at Courtney for obvious reasons and murdered her.
The real Ali killed her twin Courtney. Courtney was friends with the Pretty Little Liars. Ali didn't like Courtney.
Well, in the book she isn't. Alison hated the PLL, she was never their friend. Courtney was. Courtney was Ali's twin sister and he had mental issues. The night Ali diappeared, Courtney wore Ali's ring and pretended to be her while Ali was at home, trying to convince her parents she was Ali and not Courtney. Ali's parents sent Ali to a mental hospital because theu thought she was Courtney and Courtney died because the killer thought she was Ali.
since Courtney was pretending to be Ali, then Ali (who was pretending to be Courtney) lived in a mental institution because the REAL Courtney had a mental problem and lived in institution most of the time.
Ali's mom introduces their daughter who is Courtney (Ali's twin) then Courtney asks them to talk to her...she eventually tells them how Courtney had mental issues and that she always wanted to pretend to be Ali and the night that Ali was supposably killed it was Courtney who was killed and Ali tried to tell her parents that she was Ali but they thought that it was Courtney saying she was Ali again so they sent her to a mental hospital for years and then she came back later
ali had a twin named courtney who was the real best friend of the four courtney was the one murdered.this happened because alps mom mistakes ali as courtney and courtney as ali and courtney is mental so they sent ali to the preserve as courtney without knowing ti was the real ali so ali was hiding at the preserve.
Ali is not A, it is Mona. Ali was not actually killed either. It was her twin sister Courtney.
Yeah she is cuz Alison had a twin sister a named Courtney and when they were older Courtney put Alison in a mental hospital and so she was acting like Alison and the four liars didn't know that Ali had a twin so they thought that Courtney was Ali and Ali got out of the mental hospital and so she was mad at Courtney and Ali killed Courtney and now Ali is A because she is mad at the four liars cuz they didn't know that Courtney wasn't Ali