Kersey was last seen walking in the Hearthwood Boulevard area of Clark County, Washington on March 11, 1987, while on her way home from Mountain View High School, where she was a senior. She did not always walk home; sometimes she caught a ride with her father or with a friend. The day after her disappearance, Kersey's schoolbooks and papers were found in a field not far from her home. She has never been heard from again.

Authorities have two main suspects in Kersey's disappearance: Russell Francis Stenger, who is currently serving a life sentence for the murder of a woman who disappeared while on a walk not far from where Kersey was last seen, and an unidentified man who used to live two blocks from Kersey's home and who has a record for child molestation. The man has since left the state. Investigators continue to pursue leads in Kersey's case; they strongly suspect foul play precipitated her disappearance. Kersey lived with her mother and two siblings in 1987; her parents were divorced, and her father lived nearby. Her mother died in 1996.

In August 2003, the skull of a person between mid-teens and early twenties was found in Cowlitz County, Washington. The skull was tested against several young women missing from the general area, including Kersey, but each missing person was ruled out and the skull remains unidentified. Kersey's case is unsolved.

Some reports give the year of Kersey's disappearance as 1990, or give her age as 18.