Wendy's family left their residence to play golf at a local country club on May 17, 1975. She stayed behind at their house on Moccasin Trail in Media, Pennsylvania and was sunbathing at the time. Wendy spoke to a friend later in the afternoon and said she planned to walk to a store to purchase a gift for her brother. Wendy was last seen walking three blocks from her family's residence at approximately 3:05 p.m. at the intersection of Indian Lane and Media Station Road. She was headed towards downtown Media at the time she vanished. Wendy has never been seen again. Bloodhounds were able to track her scent to the intersection where she disappeared, but there was no trace of her elsewhere.

Wendy's family told authorities that she was very interested in religion and planned to attend a singing group rehearsal at their church on the night she vanished. Her relatives stated that Wendy would not have missed the rehearsal. Her family considered the possibility that she may have joined a religious cult-type of organization, but no evidence has been located to suggest that was the cause of Wendy's disappearance. Her case remains unsolved.