The Missouri Supreme Court and the state’s GOP Gov. Mike Parson each refused requests on Monday from an inmate attempting to avoid his scheduled execution.

Marcellus Williams, 55, is set to be executed by lethal injection Tuesday at 6 p.m. in connection with the murder of Lisha Gayle, a social worker and former newspaper reporter who was stabbed more than 40 times during a burglary at her home in St. Louis in 1998, according to The Associated Press. Williams has maintained his innocence.

Parson rejected Williams’ clemency request to spare his life and instead sentence him to life in prison. The state Supreme Court also rejected a request for the execution to be halted to allow a lower court to make a new determination about whether a trial prosecutor wrongly excluded a potential black juror due to racial bias.

His attorney argued before the state Supreme Court about alleged procedural errors in jury selection and the prosecution’s alleged mishandling of the murder weapon. The court, in a unanimous decision, affirmed a lower court ruling rejecting Williams’ claims.

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Marcellus Williams, 55, is set to be executed by lethal injection Tuesday at 6 p.m. (Missouri Department of Corrections via AP)

“Despite nearly a quarter-century of litigation in both state and federal courts, there is no credible evidence of actual innocence or any showing of a constitutional error undermining confidence in the original judgment,” Judge Zel Fischer wrote in the state ruling.

Williams’ attorneys have also made an appeal before the U.S. Supreme Court, which is still pending.

Parson said Williams’ lawyers received ample legal opportunities to attempt to make their client’s case for his innocence. The governor also claimed Williams’ attorneys were trying to “muddy the waters about DNA evidence” with allegations the courts have already rejected.

“Nothing from the real facts of this case have led me to believe in Mr. Williams’ innocence,” Parson said in a statement. “As such, Mr. Williams’ punishment will be carried out as ordered by the Supreme Court.”

The governor has never granted clemency in a death penalty case.

St. Louis County Prosecuting Attorney Wesley Bell has looked to set aside Williams’ sentence, pointing to questions about whether he is guilty. Bell plans to appeal the Missouri Supreme Court ruling to the U.S. Supreme Court, his spokesman told The Associated Press.

“Even for those who disagree on the death penalty, when there is a shadow of a doubt of any defendant’s guilt, the irreversible punishment of execution should not be an option,” Bell said in a statement.

Midwest Innocence Project attorney Tricia Bushnell said “Missouri is poised to execute an innocent man, an outcome that calls into question the legitimacy of the entire criminal justice system.”

During Williams’ original trial, prosecutors claimed he broke into Gayle’s home on Aug. 11, 1998, heard water running in the shower, found a large butcher knife and stabbed her 43 times when she came downstairs. Gayle’s purse and her husband’s laptop computer were stolen from the home.

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Joseph Amrine, who was exonerated two decades ago after spending years on death row, speaks at a rally to support Missouri death row inmates Marcellus Williams on Aug. 21, 2024, in Clayton, Missouri. (AP)

Williams was accused of stealing a jacket to conceal blood on his shirt. Williams’ girlfriend asked him why he would wear a jacket on a hot day, and she said she later noticed the purse and laptop in his car. Williams sold the computer a day or two later, his girlfriend said.

Prosecutors also pointed to testimony from Henry Cole, who shared a cell with Williams in 1999 while Williams was behind bars on unrelated charges. Cole said Williams had confessed to the killing and offered details about it.

Williams’ execution would be the third Missouri has carried out so far this year and the 100th since the state resumed executions in 1989.

This will be the third time Williams was nearing execution.

In January 2015, he was less than a week away from execution when the state Supreme Court canceled it to allow time for his attorneys to pursue additional DNA testing.

Williams was just hours away from being executed in August 2017 when then-Republican Gov. Eric Greitens granted a stay and appointed a panel of retired judges to examine the case. The panel, however, never reached a conclusion in the case.

Concerns about DNA evidence also prompted Bell to call for a hearing challenging whether Williams was guilty. But days before the Aug. 21 hearing, new testing revealed that DNA on the knife belonged to people in the prosecutor’s office who handled it without gloves following the original tests.

Missouri Gov. Mike Parson delivers the State of the State address on Jan. 18, 2023, in Jefferson City, Missouri. (AP Photo/Jeff Roberson)

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Without DNA evidence implicating any alternative suspect, Midwest Innocence Project attorneys reached a compromise with the prosecutor’s office in which Williams would enter a new, no-contest plea to first-degree murder in exchange for reducing his sentence to life in prison without parole.

Judge Bruce Hilton and Gayle’s family signed off on the deal but, at the request of Republican Missouri Attorney General Andrew Bailey, the state Supreme Court blocked the agreement and ordered Hilton to move forward with an evidentiary hearing, which was held on Aug. 28.

The prosecutor in the 2001 murder case argued at the hearing that the trial jury was fair, even though it included just one black juror. The prosecutor said he removed one potential black juror in part because he looked too much like Williams, which Williams’ attorneys say showed improper racial bias.

Hilton ruled earlier this month that the first-degree murder conviction and death sentence would stand, highlighting that Williams’ arguments had all been previously rejected, a ruling that was upheld Monday by the state Supreme Court.

The Associated Press contributed to this report.