Sasha Pieterse
Alison DiLaurentis is killed by her twin sister, Charlotte DiLaurentis, also known as CeCe Drake, in the television series "Pretty Little Liars."
Because Mr. DiLaurentis and Mrs. DiLaurentis think Alison is dead (she really isn't, Courtney is) she is thought to be Courtney. So, they send her back to the mental hospital until she is revealed in Wanted, the last book in the series. Courtney is Alison's psychotic twin sister who is really dead. Hope that helps! :)
Yes, Jason DiLaurentis.
Alison DiLaurentis accidentally blinded Jenny and found out that her and her step-brother were doing it regardless of being step-siblings. Later the real Alison DiLaurentis kills Jenna for knowing too much about the Alison/Courtney switch. See Wikipedia for more
Mr.Ford (Billy Ford) was the man that was accused of killing Alison DiLaurentis and Jenna Cavanaugh. Billy was the man that was helping build the gazebo in Alison's backyard and helped with Jenna's plumbing system. Billy really didn't kill the girls though as evidence leads you and the police in the book. Alison killed Alison as the medium said.
Alison.
Sasha Pieterse
Courtney DiLaurentis is Alison DiLaurentis's identical twin sister who appeared in the Pretty Little Liars book series, but not in the television show. In the books, Courtney is sent to a mental institution by her parents, who mistakenly believe she is Alison. The mix-up plays a significant role in the overall storyline.
The concept of who killed Alison DiLaurentis changes throughout the entire Pretty Little Liars series. Many people who have been accused with this task are Toby Cavanaugh, Spencer Hastings, Emily Fields, Aria Montgomery, Hannah Marin, Mrs. Hastings (Spencer's mother), Ian, Melissa Hastings, Billy and Jenna. Alison was not actually killed, her twin sister Courtney was. Read all of the Pretty Little Liars series and this answer will make much more sense!
In the books, Jason DiLaurentis does know. He is closest to Courtney out of the twins
Hanna's and Alison's roommate in the mental hospital.
No. But Ian was framed by the real A, Alison