Thomas in Ausable Township, Michigan on August 3, 1980, while on her way to pick up her daughter from the baby-sitter. Her borrowed brown AMC Matador stalled at the intersection of U. S. 23 and River Road. Some area youths helped her get it started again, but it stalled once more on Sunset Street about two blocks from the baby-sitter's home and barely a mile from the local police station.

Thomas was seen on Sunset Street 11:15 p.m., getting into a blue pickup truck driven by a bearded Caucasian male. The truck drove off in the direction of Old U. S. 23. Thomas was never seen or heard from again.

In 2004, investigators arrested Jimmie Allen Nelson in Houston, Texas and charged him with lying to police and obstructing the investigation into Thomas's disappearance and probable murder. In January 2005, he was charged with murder and additional counts of perjury. He is the brother-in-law of the baby-sitter Thomas was going to see the day of her disappearance, and he lived on Sunset Street worked at an area logging company in 1980. Police investigated Nelson shortly after Thomas's disappearance, but he was not a serious suspect in the case because a violent federal fugitive had been seen in the area around the time she disappeared and the authorities thought it was he who had abducted Thomas.

Investigators interviewed the fugitive in prison thirteen years later, but he had an alibi for the time Thomas disappeared, so they returned their focus to Nelson. He gave inconsistent statements about the day Thomas vanished. At first he had denied seeing Thomas the day of her disappearance, but later admitted that he gave her a ride when her car broke down. He said he took her to a friend's home and then to Wiltse's Restaurant, where employees who were cleaning the establishment let her inside. He said he had not told authorities about it earlier because Thomas asked him not to.

In October 2005, the murder charge and nine of the perjury charges against Nelson was dismissed for lack of evidence; the judge stated he believed Thomas was deceased, but there was insufficient evidence to prove she was murdered. The murder charge dismissal is being appealed by prosecutors, and if additional evidence is located, Nelson can be charged with murder again. In October 2006, he was convicted of five counts of perjury and one count of obstruction of justice, but acquitted of eight other perjury charges. He was sentenced to one year in jail and two years on probation; he could have faced a maximum of twenty years' incarceration. As Nelson was given credit for time served while awaiting trial, he spent less than a month in custody following his sentencing.

Police believe Thomas was murdered and her death was a hate crime; she was an African-American woman living in a predominantly Caucasian, conservative area. Her case remains unsolved.