This article revolves around the death of Jessica DiLaurentis. She was murdered by her twin sister Mary Drake in "A is for Answers", and buried in the Hastings' backyard by Charlotte DiLaurentis, who discovered her body outside the DiLaurentis house. Her body was found by Pepe in the Hastings' backyard in "Whirly Girlie".
Jessica had moved back into her old home at the beginning of Season 4. Her return was mysterious, and the Liars felt unsure about why she had returned to Rosewood over a year after her daughter's body was found in her backyard.
Several days before Jessica's death, her identical twin sister Mary Drake, returned to Rosewood to see her daughter, Spencer Hastings, whom she had given up for adoption years before. While breaking into the Hastings house to take a look at Spencer, Mary was spotted on her way out by Spencer's father Peter Hastings, whom he at first he thought was Jessica, she revealed herself as Mary.
Mary begged Peter to help her get revenge on Jessica because she had lied about Mary's eldest child, Charles, being dead, when he had actually transitioned into Charlotte DiLaurentis. Instead, Peter decided to team up with Jessica to kill Mary, so he could protect his family.
During Season 4A, Mary came to the Hastings house again to talk with Peter, hoping to convince him let her see Spencer. However, Peter refused, believing her to be unstable and dangerous. Jessica entered the Hastings house at that moment and was shocked to see Mary. She addressed Peter saying, "I thought we were taking care of this". It was then that Mary realized what they were planning and decided to get revenge on both of them.
Day of Death
Jessica was hosting a Bridal Show for charity to raise money for starving children. Detective Holbrook shows up at her house in the morning to update her on the investigation into Alison's murder. He told her that they had a court order to exhume "Alison's" body, as recent evidence suggested that Alison was not actually the one in the grave. Jessica seemed angered by this motion.
While the Bridal Show was taking place, Spencer saw Jessica give a suitcase to CeCe Drake. Jessica was later taken to the police station and informed that Alison was still alive. She shared a conversation with Peter Hastings in which he asked her if they still had an agreement, as the police were asking pointed questions about Spencer. She told him that she could not think about anything else but the fact that her daughter was still alive. Officer Maple then asked to speak to her in private.
Sometime later that evening, Jessica returned home and wrote an email to Charlotte stating, "I can't protect you anymore". However, she did not send the email, and probably went to speak to her in person.
At some point, Mary intercepted the medication Peter was going to supply Jessica to kill Mary, and swapped Jessica's low blood pressure pills with Peter's pills. Peter's pills contained Losartan, which is used for people with high blood pressure. When Jessica took these pills, her heart stopped working. Mary then succeeded in framing Peter for Jessica's death.
Charlotte, after escaping police custody, snuck back to the DiLaurentis house to say goodbye Jessica before finally leaving Rosewood. However, when she arrived, Jessica's body was lying outside the DiLaurentis house. Charlotte tried to wake her mother before discovering that she was dead, and sobbed over Jessica and begged her to come back. Later, for unknown reasons, Charlotte decided to bury Jessica in the backyard of the Hastings' house, and filmed it so she could later send it to Alison as a threat to behave. Charlotte then left the backyard, and resumed her plans of being A.
Alison returns to Rosewood the same night and meets her father at the police station. He takes her home where Jessica is nowhere to be found, which surprises both of them. The following morning, a dog, Pepe, is dropped off at the DiLaurentis house, as Jessica had planned to adopt her. Alison, despite Jason's chagrin, decided to save the dog from being euthanized and take Pepe despite her mother not being there. In the meantime, Kenneth visited Ashley Marin to ask her if she could look into Jessica's emails, and find out where she was. as she was currently missing. Hanna later discovered the email Jessica had been meaning to send to an originally unknown person. That night, Kenneth and Jason argued as Kenneth believed his son knew where Jessica was, despite Jason's claims that she didn't.
Later on, Pepe begins barking at something in the Hastings' backyard. The Liars and Jason go outside to find Jessica's hand sticking out of the ground, as Pepe had dug up that much of Jessica. They call the police, and Jessica's body is taken away by the Rosewood County morgue, as Alison stands in the center of scene in shock.
An initial autopsy is unable to determine Jessica's cause of death. Alison later tells Spencer that a toxicology report confirmed that somebody had switched her blood pressure medication, causing her heart to fail. Spencer originally suspects that one of her parents killed Jessica, but later events stopped her from pursing this.
It isn't until years later, that Peter admits to Spencer and Veronica that he, alongside Jessica, had planned to kill Mary Drake, but Mary had found out and killed Jessica out of revenge. Later, Mary confesses to killing her sister and is arrested for the murder of her sister (and Archer Dunhill's) by Detective Tanner.
- Mary Drake is the murderer of Jessica, as revealed in "Power Play".
- Originally, Jessica and Peter planned to kill Mary together, however, Mary found out about this and killed Jessica first with Peter's medication to frame him.