Missouri is set to execute 55-year-old death row inmate Marcellus Williams on Tuesday evening — despite pleas from prosecutors and even his victim’s family.

Missouri’s governor, Mike Parson, and its supreme court said Monday that sufficient evidence exists for the state to take Williams’ life for the 1998 stabbing murder of Felicia Gayle, a social worker and former reporter at the St. Louis Post-Dispatch.

The state’s decision to push forward with the execution is among the more controversial in recent years, with the same prosecutor’s office that convicted Williams now sounding the alarm he may actually be innocent.

Gayle’s family has even spoken out in favor of clemency, signaling that a life sentence without parole is the appropriate punishment for Williams given the circumstances.

Williams has maintained for decades that he didn’t enter Gayle’s home on Aug. 6, 1998, and fatally stab her 43 times with a butcher’s knife before stealing her purse and her husband’s laptop, as prosecutors alleged.

Investigators recorded fingerprints, footprints, hair, and DNA on a kitchen knife at the crime scene, but the investigation went on for more than a year before police arrested Williams. It was revealed during a trial that Williams’ DNA did not match the forensic evidence recovered from the crime scene.

Yet, Williams was still convicted of murder in 2001 and sentenced to death after damning testimony was heard from his cellmate, who claimed he confessed to the killing while in lockup for a separate crime, and from Williams’ girlfriend, who said she saw the stolen purse and laptop in William’s car.

Williams’ extensive criminal record surely didn’t help him win favor with jurors, either. At the time of his conviction, he was serving a 50-year sentence for an unrelated robbery.

Still, defense attorneys argued that Williams’ ex-cellmate and girlfriend were both gunning for the $10,000 reward put forward by Gayle’s family, which made them willing to make up lies if it’d personally benefit them. In the end, neither received the payout.

Jailhouse informants are known to be particularly problematic, with the University of Michigan finding that they’re involved in 23 percent of death penalty exoneration cases.

Williams escaped execution at the final hour twice previously, first by the state Supreme Court in 2015 and again in 2017 when then-Gov. Eric Greitens, a Republican, granted Williams a reprieve and asked prosecutors to review DNA evidence again. That DNA evidence may have exonerated Williams, but it was determined to have been spoiled by members of the prosecutor’s office who touched the knife without gloves before the trial.

Now its Parson, a former sheriff of 11 years, who is sitting in the governor’s mansion in Jefferson City. He’s been in office for 11 executions and has never granted clemency.

Parson justified his decision in a statement on Monday, writing that “no jury nor court, including at the trial, appellate, and Supreme Court levels, have ever found merit in Mr. Williams’ innocence claims.”

The Midwest Innocence Project says it will push for Williams’ clemency up until 6 p.m. CST Tuesday, when he’s scheduled to be killed by lethal injection.