The Murder of Cassandra "Casey" Williamson

Casey was not selected at random in the traditional sense. Johnson had known the Williamson family for years through his older sister and had been permitted into the home on multiple occasions. Court records established that he began targeting Casey specifically two days before the murder, after spending time at the Rehm residence and observing her.

He later stated that he decided Casey was someone he could overpower and that the morning of July 26 presented what he described as his best opportunity. His confession confirmed the killing was planned, not impulsive.

The primary weapons were a brick and a large rock recovered from the pit at the abandoned glass factory. Johnson was found soaking wet when detained, consistent with his confession that he washed himself in the Meramec River after the killing. Semen recovered from Johnson's shorts was noted in court records as consistent with an attempted sexual assault.

Casey's body was found buried beneath rocks and debris in a shallow pit less than one mile from where she was last seen. The scene was consistent with the account Johnson provided during his confession.

After attempting to sexually assault Casey in the pit at the glass factory and meeting resistance, Johnson struck her in the head with a brick at least six times. She remained alive and attempted to flee within the pit. He struck her again as she fell to her knees and tried to crawl away, eventually fracturing the right side of her skull.

The autopsy confirmed cause of death as blunt force trauma to the head, with skull fractures and bruising of the scalp and brain. Additional injuries were documented to her arms, shoulders, legs, and back, consistent with her attempts to resist the assault.

Johnson provided both verbal and audiotaped confessions to investigators on the day of the murder. His account described the precise route taken to the factory, the layout of the pit, the sequence of the assault, and the location of Casey's body. Each element was independently confirmed by physical evidence at the scene.

St. Louis County Police Chief Ron Battelle publicly confirmed that Johnson's statements established the killing was planned in advance, not a spontaneous act. Former homicide investigator Paul Neske, who conducted the initial questioning, described it as the most violent and brutal case he had encountered in his career.

Johnson had been confined to a state psychiatric facility for schizophrenia and released six months before the murder. At the time of the killing he had stopped taking his prescribed medication. His defense at trial centered on schizoaffective disorder and a claim that hallucinations impaired his ability to form criminal intent; the jury rejected this on all counts.

In his final appeals, Johnson claimed he believed Satan was using the State of Missouri to execute him to bring about the end of the world and argued this rendered him incompetent to be put to death. The Missouri Supreme Court, the 8th Circuit, and the U.S. Supreme Court all declined to intervene. The Missouri Attorney General's office argued medical records showed Johnson could manage his illness through medication.

Johnson had a prior felony conviction for burglary and had been institutionalized for schizophrenia before his release. He was homeless at the time of the murder and had no stable residence. He was 24 years old. He had been known to the Williamson family for years and was considered sufficiently trusted to sleep on the family's couch.

Johnson's older sister had been a childhood best friend of Casey's mother Angie, who had even babysat Johnson as a child. The family's familiarity with him was the means by which he gained access to Casey. Former prosecutor Bob McCulloch stated plainly that despite his documented psychiatric history, Johnson knew exactly what he was doing.