Mary Ann Knightly's disappearance in February 1998 remains a mystery. She was last seen with her husband, Roy, at their home in Bear, Delaware at 11:30 p.m. on February 18th. According to Roy, Mary Ann packed a bag and left, saying she needed to get away for a while and was heading to Florida to visit her sister. Roy fell asleep and when he woke up at 1:30 a.m., she was gone. However, Mary Ann never arrived in Florida.

On the evening of February 18th, Mary Ann borrowed a van from her mother, saying she would return it the next day. Roy returned it, claiming that Mary Ann had asked him to do so on her behalf. It is unclear how Mary Ann intended to travel to Florida, and it is unknown how much money she had with her when she disappeared.

According to reports, Mary Ann had a history of leaving home for up to three days at a time without informing anyone where she was going. Her mother reported her missing on February 26th. Roy has been named a person of interest in Mary Ann's case, and he has never been cleared of suspicion. Authorities suspect foul play in her disappearance, which remains unsolved.