Sylvia was last seen in Campbell, California on October 31, 1995. She said goodbye to her boyfriend and boarded a bus en route to a light rail station, where she planned to catch a train to her grandmother's home in San Jose. She never arrived and has never been heard from again.

Wilbur Atcherley pleaded guilty to Sylvia's murder in 2011, sixteen years after her disappearance. He was already serving 61 years to life in prison at the time; he had abducted another female and tried to kill her in 1999. While in prison, on the fifth anniversary of Sylvia's disappearance, Atcherley contacted authorities and confessed to killing her. He said he met at the light rail station and she got into a taxi with him. He took her to a remote area in New Almaden, sexually assaulted her and killed her, then left her body in a creek bed. Investigators checked his story and found cab records indicating a fare from San Jose to New Almaden on that date. Atcherley had 15 years added to his sentence for her death.

Atcherley led police to the spot where he said he'd left Sylvia's body, but a search turned up nothing. Authorities believe her remains were washed away.