How does Alison try to kill the girls at the end of the Pretty Little Liars series?
Well assuming she isnt alive (but knowing the books she is still alive) in the 8th book and I'm pretty sure in another occasion she tried burning the girls alive in the lake house and spencer's barn.
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!