Shannon was last seen by a friend at the Western Sizzlin Steakhouse in Lugoff, South Carolina at about 2:30 p.m. on February 4, 1999. They had attended a meeting of Sistercare, a battered women's support group, and Shannon had dropped off her friend before leaving. She has never been heard from again. She was reported missing after she missed her mother's February 11 wedding.

Foul play is suspected in Shannon's case. She was going through a contested divorce at the time of her disappearance and missed several court dates relating to it, as well as her mother's wedding, which is uncharacteristic of her. Shannon left all of her personal belongings, including her medication, behind at her home. There were no signs of a struggle at the residence but no indication that she was planning to leave either. She did take her car, a burgundy two-door 1998 Oldsmobile Cutlass with South Carolina license plates numbered 605-CJY. It has not been located.

Shannon's home in Kershaw County, South Carolina was destroyed by fire a year before she vanished. It was worth $90,000, but she did not collect any insurance on it. Police are still investigating the fire and are unsure what, if anything, it has to do with her later disappearance. Shannon's husband was required to make $400 monthly alimony payments to her until 2003, four years after she vanished. He stated that prior to her disappearance, she had been hospitalized for mental illness. The Shannons have two sons, who were in their father's care in February 1999. Shannon's case remains unsolved.