Courtney was a big secret because she was always in a mental institution - the same one Hannah is sent to.
That Ali had a twin sister named Courtney.
No. Courtney is dead
Courtney
They might or it could be the 4 girls secret
Courtney is alison's twin sister, who pretended to be her
You find out about Courtney in the book Wanted.
Courtney was in the hospital because she had mentel issues.
Actually no...
Alison
Suffication
by hands
The real Ali killed her twin Courtney. Courtney was friends with the Pretty Little Liars. Ali didn't like Courtney.