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]
Pretty Little Liars (book series) The series is loosely divided into four arcs, chronicling the introduction and reveal of each "A". Set in the suburbs of Philadelphia The series follows the lives of four teenage girls nicknamed the Pretty little Liars or simply the Liars, whose clique falls apart after the disappearance of their Queen bee leader, "Alison DiLaurentis". Three years after her disappearance, the girls begin receiving threatening messages from an anonymous character named "A," who threatens to expose their secrets, including long-hidden ones they thought only Alison knew. Shortly after the messages begin, Alison's body is discovered buried in her yard. The books progress with the four girls trying to figure out the identity of "A" and facing many dangerous obstacles and twists as they do so.