Pyle Peters was last seen at at Forest Hills Central Middle School in the 5800 block of Ada Drive southeast in Grand Rapids, Michigan at 5:00 p.m. on February 5, 1981. She was at her six-year-old brother's wrestling practice with her mother when she said she was going to the women's restroom and would be back shortly. Pyle Peters never returned and has not been heard from since. Pyle Peters apparently never arrived at the restroom; no one saw her anywhere near there. She was last seen walking out the door of the gymnasium; accounts differ as to whether she was going to a friend's home or merely wanted to smoke a cigarette. She left her wallet, purse, makeup, jewelry, clothing and several hundred dollars behind at home.

Arthur Diaz, the school's custodian, was considered a possible suspect in Pyle Peters's disappearance for many years. He stated he was cleaning a school office the night of her disappearance and never saw her. Authorities checked the school incinerator on the theory that someone might have tried to burn her body, but found no evidence. Diaz is no longer a suspect in Pyle Peters's case. Another suspect is a local man, Bruce Bunch, who was seventeen years old and a high school junior in 1981. Over twenty years after Pyle Peters's disappearance, a female acquaintance of Bunch told police he told her a story about running over a girl at a school. Bunch allegedly said he either ran or backed over the girl, took her body to Snow Avenue and buried it under a pile of rocks. This story has not been confirmed, but Bunch remains a suspect in Pyle Peters's disappearance. His first wife stated he was violent and abusive towards her and, after drinking heavily, would sometimes black out and have no memory of what he did. She stated he once pushed her out of a moving vehicle and broke her ankle, and on another occasion threatened to run her off the road. Bunch died of a heart attack in 2008.

Two days before she disappeared, Pyle Peters had a physical altercation at school with two other girls. They were fighting over a boy, and the two girls allegedly threatened Pyle Peters and told her to stay away from the boy. It's unclear whether the incident had anything to do with her later disappearance. Pyle Peters was not having any serious problems with her family when she disappeared, she was a good student, and she does not have a prior history of running away from home. Several possible suspects were questioned after her disappearance, but no on has ever been charged. She was an eighth-grader in 1981, and aspired towards a career as a model. She is originally from California, and her biological father was living there in 1981. Her mother and stepfather, with whom she lived, moved to Arizona after her disappearance. Her stepfather has been ruled out as a suspect in her case.

Pyle Peters was declared legally dead in 1991. In 2008, authorities reopened the investigation into her disappearance and appealed for anyone who was at the school that day to contact them. Her Her case remains unsolved.