Marcellus Williams, a death row inmate in Missouri, was executed by lethal injection on Tuesday for the 1998 murder of Lisha Gayle, a former journalist who was brutally stabbed in her suburban St. Louis home.

Williams, 55, died after 6 p.m. CDT at a state prison in Bonne Terre in Francois County, about 60 miles southwest of St. Louis, Williams’ attorney confirmed to ABC News.

The death penalty case received national attention. Williams continued to maintain his innocence, the victim’s family opposed the execution, and the prosecution filed appeals at all levels.

“Marcellus Williams should have been alive today. There were multiple points in the timeline where decisions could have been made that would have spared him the death penalty. When there is even a shadow of a doubt of innocence, the death penalty should never be an option. This outcome did not serve the interests of justice,” Wesley Bell, chief district attorney for St. Louis County, said in a statement after the execution.

The United States Supreme Court on Tuesday rejected two separate appeals to save Williams’ life, hours before his execution, over the objections of Justices Ketanji Brown Jackson, Elena Kagan and Sonia Sotomayor.

Williams’ attorney Tricia Rojo Bushnell released a statement after the Supreme Court’s decision, saying, “Tonight, Missouri will execute an innocent man, Marcellus “Khaliifah” Williams.”

“As dark as today is, we owe it to Khaliifah to build a better future. We are grateful to the St. Louis District Attorney for his dedication to truth and justice and all he did to try to prevent this unspeakable injustice. And to the millions of people who signed petitions, called and shared Khaliifah’s story,” Bushnell said.

On Monday, Missouri Gov. Mike Parson and the state Supreme Court rejected a request to halt the execution.

In a statement to ABC News, Parson said, “No jury or court, including the trial court, the appellate court and the Supreme Court, has ever found Mr. Williams’ claims of innocence valid.”

“Ultimately, his conviction and death sentence were upheld. Nothing in the facts of this case led me to believe in Mr. Williams’ innocence,” Parson added.

Williams was charged with first-degree murder in 1999 for the killing of Gayle, a social worker and former reporter for the St. Louis Post-Dispatch. He was found guilty in 2001.

Prosecutors in Williams’ original trial alleged that he broke into Gayle’s home in August 1998 and stabbed her 43 times with a large butcher knife, according to court documents. Her purse and her husband’s laptop were stolen after the attack.

The kitchen knife used in the killing was still inside Gayle’s body, according to court documents. Blood, hair, fingerprints and shoe prints believed to be the killer’s were found around the home.

Williams’ defense argued that his DNA was never found on the murder weapon and that two unknown sources of DNA would lead investigators to the real killer.

DNA evidence discovered in August showed that the former prosecutor and the investigator who handled the original trial did not wear gloves when handling the murder weapon, leaving their DNA on the knife, revealing the source of the unidentified DNA, which did not belong to an unknown killer.

In his statement Monday, Parson accused Williams’ attorneys of “attempting to cloud the DNA evidence” with claims that had previously been rejected by the courts.

“Nothing in the facts of this case has led me to believe in Mr. Williams’ innocence,” Parson said.

Williams’ execution is the third in Missouri this year and the 100th since the state reinstated the death penalty in 1989.

ABC News’ Abigail Cruz and Tesfaye Negussie contributed to this report.