PLL, S2-E24: If These Dolls Could Talk

After having a strange vision of Allison, Spencer looks again at the newspapers in Ali's bag and finds a bunch of personal ads between Ali and A. The girls visit the meeting place set up in one of the ads, which is the doll hospital they recently visited. Although the owner claims to not know anything about the creepy voodoo doll given to Ali, a young boy named Seth mentions Ali and the two people (a man and a woman) who wanted to hurt her. Suspicion falls on Jenna and Melissa, but the girls set up a trap - Mona and Caleb making out in front of Melissa - to see if she texts Hanna as A. When the text comes through, Hanna is convinced that Melissa is A. Spencer makes them stop one last time at the doll hospital for confirmation, but they are frightened away by an eerie doll display that threatens them with death. They plan on handing over all the evidence to the police just as the cops arrive at Spencer's to arrest Garrett for the murder of Allison.

Source: TV Fanatic