Royce disappeared with his mother, Kathleen. They were last seen together in Tulsa, Oklahoma on March 23, 1979. Kathleen worked at Roger's Records in the 5000 block of north Peoria Avenue and had access to concert tickets as a result of her job. At 11:30 p.m. on the day of her disappearance, she called some friends and said she was going to their home to give them tickets and would be there within an hour. Kathleen was driving her father's car, a 1969 Chrysler. She and Royce never arrived and have never been heard from again.

Kathleen is divorced and left behind a ten-year-old son, Eamon, whom she was very close to. She dropped him off at his father's place of business the evening of March 23. Eamon was supposed to only stay with his father for a few hours. Later that evening, Eamon's father dropped him off at Kathleen's house without realizing Kathleen wasn't there. The house was locked and Eamon didn't have a key, so he crawled in through a window and went to bed. When he woke up in the morning and realized his mother still wasn't home, he called her best friend, who called Kathleen's parents.

On March 25, Kathleen's father's vehicle was found locked and abandoned at the corner of Ute Street and Peoria Avenue in Tulsa. There was no sign of the Hensons at the scene, but Kathleen's coin purse and identification were inside the car. She wasn't carrying any money, extra clothing, or diapers or bottles for Royce at the time of her disappearance. Kathleen's loved ones don't believe she knew anyone living in the area where her car was found. When authorities searched the Hensons' home, they found no indications of a struggle.

Prior to her disappearance, Kathleen mentioned being afraid of a male acquaintance who was involved with criminal activity. At first her parents believed she'd left of her own accord to get a break, but as weeks passed and no one heard from her, they concluded something else must have happened to her and Royce. There's been no sign of either of them since 1979.

Foul play is suspected in Kathleen and Royce's disappearances, which remain unsolved.