A man who lured a 6-year-old girl to an abandoned glass factory in Missouri two decades ago, where he beat her to death after trying to sexually assault her, was executed Tuesday.

Johnny Johnson, 45, was injected with a lethal dose of pentobarbital at a state prison in Bonne Terre for killing Casey Williamson on July 26, 2002 in Valley Park, a suburb of St. Louis.

Johnson was pronounced dead at 6:33 p.m. CT, the Associated Press reported, citing authorities.

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“Johnny Johnson’s crime is one of the most horrific murders that has come across my desk,” Missouri Gov. Mike Parson said in a news release. “Casey was an innocent young girl who bravely fought Johnson until he took her life.”

Johnson, who was previously diagnosed with schizophrenia, apologized for his actions in a brief statement before his last breath.

“God Bless. Sorry to the people and family I hurt,” Johnson’s statement said, according to the AP.

Casey’s mother was best friends with Johnson’s older sister at the time of her daughter’s murder. The night before the girl was killed, Johnson slept on the couch in the home where Casey’s family was also staying. He had attended a barbecue at the residence that evening. 

On the morning of July 26, 2002, Casey and Johnson vanished from the home they were staying at and her parents called police. The girl’s body was later found in a pit, buried under rocks and debris, less than a mile away from her home, according to St. Louis-based station Fox 2.

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Johnson later admitted to police that he kidnapped Casey that morning with the intent of raping and killing her, the station reported.

He carried Casey — who was still in her nightgown — on piggyback to an abandoned glass factory, where he exposed himself to her.

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While trying to defend herself from the assault, Johnson beat the girl over the head with a brick and a large rock, before cleaning himself off in a nearby river, the outlet reported.

“It was more violent and brutal than any case I’ve ever seen,” said former St. Louis County homicide investigator Paul Neske, who questioned Johnson the day of the murder, according to the AP.

In 2005, Johnson was found guilty of first-degree murder, armed criminal action, kidnapping and attempted rape. The judge later sentenced him to death by lethal injection.

In June of 2023, the Missouri Supreme Court rejected an appeal that argued Johnson’s schizophrenia prevented him from understanding the link between his imminent execution and his crimes.

According to his attorneys, Johnson had neglected to take his medication for schizophrenia prior to Casey’s murder because he said it made him “feel like a zombie.”

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“Johnson has delusions about the devil using his death to bring about the end of the world,” they noted in their briefs.

Former St. Louis County Prosecutor Bob McCulloch claimed the delusions were “nonsense,” adding that Johnson imposed “unspeakable horrors” upon Casey, per the AP.

“He’s got some issues — significant issues,” McCulloch said just moments before Johnson was put to death. But “he knew exactly what he was doing.”

Among those present at the execution were several members of Casey’s family, as well as the former prosecutor and police investigator who were involved in the case.

Johnson’s execution is the 16^th in U.S. this year and the fourth in Missouri.