who tried to kill alison dilaurentis in the show
Alison DiLaurentis After Ian Thomas is pushed down by "A" from the top of a bell tower and his body goes missing, the girls are forced to keep their friendship a secret and to maintain therapy sessions with Dr. Anne Sullivan to discuss about Alison's absence in their lives, a fact that their parents believe to be the reason why the girls are behaving strangely.[16] Days after, through Spencer's sister Melissa Hastings, the girls find Thomas' dead body, accompanied by a suicide letter in which he admits that he killed Alison.[17] Following, the girls continue to be threatened by "A." Garrett Reynolds is arrested for Alison's murder after Jenna Marshall hands the Rosewood Police Department a missing page of Alison's autopsy.[18] The second season ends when Mona Vanderwaal—a Rosewood High student and one of Alison's victims of bullying when she was alive—is revealed as "A."[19]
Charlotte Drake In the mid-season finale of the sixth season "Game Over, Charles", CeCe is revealed to be the mysterious antagonist that has tormented the Liars throughout their senior year. At the ending of the previous episode, CeCe (then unknown) abducts Alison and takes her to Radley Sanitarium, where she recounts her story to Ali. Meanwhile, the Liars assist through a live feed in a vault at the Carissimi Group. Drake reveals to have been born as a boy named Charles DiLaurentis, and when she was 7 years old, she gave Alison a bath, but accidentally dropped her in the scalding hot water. Ali was saved by Kenneth, but as a consequence Charles was admitted to Radley. According to CeCe, as a child she frequently asked her mother to purchase her dresses but Kenneth despised his son for being feminine, so he used the bathtub incident as an excuse to send him away. Despite feeling lonely while residing at Radley, Jessica paid a visit to Charles as often as she could, in an attempt to make him feel less alienated.