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]