Alison's Burier is the person who buried Alison DiLaurentis alive on September 1st, 2009. In A is for Answers, it was revealed to be Jessica DiLaurentis. In Game Over, Charles, it was revealed that she was protecting her daughter, Charlotte DiLaurentis, who had hit Alison with a rock under the impression that she was Bethany Young.
After Alison had crossed most people off her "A" list, she made her way back home. As she walked up to her house, she saw her mother, Jessica DiLaurentis, looking at her from the window. Behind her, Charlotte DiLaurentis picked up a rock and followed Alison (who she believed was Bethany) to the front of the house. Jessica's face turned to shock as Charlotte slammed the rock into the back of Alison's head, knocking her unconscious. Charlotte realised her mistake and Jessica rushed out to the front yard in panic. Jessica decided to cover for Charlotte, as exposing what she did would expose the fact that she had faked her child's death to her husband. Under the impression that Alison was dead, Jessica dragged her body to the back yard and buried her where the gazebo was being constructed. Distraught, she angrily asked Charlotte "what have you done?!" repeatedly. Charlotte begged her mother to forgive her, as she never meant to hurt Alison and believed she was hitting Bethany.
Unbeknownst to Jessica and Charlotte, Alison began to regain consciousness while being buried, although she had temporary paralysis. She heard her mother speaking to somebody, although she could not tell who it was.
After Jessica finished burying her, Alison managed to stick her hand out of the ground in a desperate plea for help. Carla Grunwald came to the DiLaurentis back yard, as she had a bad feeling something would happen. She pulled Alison out of her shallow grave and took her to hospital, although Alison later ran away, still in fear for her life.
Jessica lived the rest of her life believing her daughter was dead and did not realise that the body that had been found a year later under the gazebo was in fact that of Bethany Young, who was supposedly killed by Mona Vanderwaal (S6xE10) and been buried by Melissa Hastings under the impression that she was Alison. She discovered the truth the night she was murdered by an unknown person.
It was commonly believed that Alison's Attempted Killer and burier were the same person until "A is for Answers", where it's revealed that Jessica is her burier, not her killer. She was inside, but saw who hit her. It's revealed in "Game Over, Charles" that Charlotte DiLaurentis is her attempted killer, although it wasn't on purpose.