A federal appeals court panel has halted next month’s planned execution of a 45-year-old Missouri man convicted of killing a 6-year-old girl, though the state is appealing the ruling.

The three-judge panel of the 8th U.S. Circuit Court of Appeals on Tuesday voted 2-1 to stop the execution of Johnny Johnson, who is scheduled to receive a lethal injection next Tuesday at the state prison in Bonne Terre for killing Casey Williamson after trying to sexually assault her in 2002.

The Missouri Attorney General’s Office responded by asking that the full 8th Circuit court reconsider the case, which will likely end up before the U.S. Supreme Court before the scheduled execution date.

Attorneys for Johnson have claimed he isn’t mentally competent to be executed because his schizophrenia prevents him from understanding the link between his crime and the punishment. They have also said Johnson has delusions about the devil using his death to bring about the end of the world.

The Missouri Supreme Court in June declined to halt the execution based on the mental health claim. The attorney general’s office challenged the credibility of psychiatric evaluations of Johnson and contended that medical records indicate he is able to manage his mental illness through medication.

Johnson lured the girl to an abandoned glass factory, even carrying her on his shoulders on the walk to the dilapidated site. When he tried to sexually assault her, Casey screamed and tried to break free. He killed her with bricks and rocks, then washed off in the Meramec River. Johnson confessed to the crimes.

Casey’s disappearance set off a frantic search involving first responders and volunteers. Her body was found in a pit less than a mile (1.6 kilometers) from her home, buried beneath rocks and debris.

The execution would be the fourth in Missouri this year. Five of the 15 U.S. executions this year have been in Texas, Florida has carried out four, Missouri has conducted three, two have happened in Oklahoma and one took place in Alabama.

Previous executions in Missouri this year included Amber McLaughlin, 49, who killed a woman and dumped the body near the Mississippi River in St. Louis. McLaughlin’s execution in January was believed to be the first of a transgender woman in the U.S.

Raheem Taylor, 58, was executed in February for killing his live-in girlfriend and her three children in 2004 in St. Louis County. Michael Tisius, 42, was executed in June for killing two central Missouri jailers during a failed attempt to help another man escape from a rural jail in 2000.