Wallace was last seen playing at Point Defiance Park in Tacoma, Washington on January 10, 1983. He was accompanied by his father, Stanley Lee Guidroz, at the time. According to his father, Wallace began to play with a female child about his age, as well as the girl's mother, near a duck pond. Stanley stated he left them and went for a walk around the pond with a man whom he assumed was the little girl's father. The two men shared a beer. When Stanley returned twenty-five to forty minutes later, his son was gone, as were the woman and child. Stanley and the man agreed to split up and search for them. They went in opposite directions and the man never came back. Stanley searched for his son for two hours before alerting police at 7:42 p.m. Wallace has never been heard from again.

Authorities made composite sketches of the man and woman. The sketches are posted below this case summary. The man, woman and child were never identified. Investigators are not sure if they were involved in Wallace's disappearance, but they are sought as witnesses. The man is described as Caucasian, in his late twenties to early thirties in 1983, and about 6'0 tall with a medium build. He had shoulder-length, sandy brown hair, a moustache and a beard, and he wore a baseball cap. The woman is also Caucasian, 5'2 and 115 to 120 pounds, with light blonde hair that fell below her shoulders and long eyelashes. She was in her early to mid-twenties in 1983. The girl is described as Caucasian with long blonde hair; she was about three years old.

After Wallace's disappearance became public, a woman called police to say she and her children had been at Point Defiance Park the day the child disappeared and had seen a man and woman, and the man matched the description of the man Stanley saw. The woman stated the couple had tried to abduct her children twice. Her account has never been verified.

Stanley and Wallace's mother, Chom Guidroz, divorced two years after Wallace's disappearance. Chom moved to Illinois, where she died in 1995 at the age of 37. Stanley moved back to his native Louisiana in 1986. In 2011, he was charged with second-degree murder in the stabbing death of his wife, Pepettra Guidroz. A photo of Stanley at the time of his arrest is posted below this case summary. He allegedly killed her during an argument, then drove her car, with her body inside, to a city a hundred miles away and turned himself into the police there. They had been married for eight years. According to Pepettra's relatives, they often argued and he was abusive towards her. He is expected to stand trial sometime in 2012. If convicted, he faces a sentence of life in prison.

Wallace's case got renewed media attention after Stanley's murder arrest. Authorities stated he'd never been ruled out as a suspect in his son's disappearance. In June 2011, they dug for his body in a waterfront are along Ruston Way in Tacoma. Police said they'd been directed to the site by Stanley. Nothing was located, however, and investigators believe Wallace's remains may not be recoverable. The medical examiner's office issued a death certificate for him, listing the cause of death as blunt force injury to the head and the manner of death as a homicide.

In 2012, authorities announced they expected to file homicide charges against Stanley for Wallace's presumed death, and would extradite him to Washington once the murder case in Louisiana was concluded. Wallace's case remains unsolved, however, and his body has never been found.

Left: Sketch of man wanted for questioning;
Center: Sketch of woman wanted for questioning;
Right: Stanley Guidroz in 2011