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

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

The death penalty trial attracted national attention: Williams maintained his innocence, the victim’s family opposed the execution, and his prosecution filed appeals at every level.

“Marcellus Williams should be alive today. There were several points during the course of the trial where decisions could have been made that would have spared him the death penalty. If there is even the slightest doubt about his innocence, the death penalty should never be an option. This outcome did not serve the interests of justice,” St. Louis County Chief Prosecutor Wesley Bell said in a statement after the execution.

The United States Supreme Court on Tuesday rejected two separate requests to spare Williams’ life, an hour before his execution, despite objections from Justices Ketanji Brown Jackson, Elena Kagan and Sonia Sotomayor.

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

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

On Monday, Missouri Governor Mike Parson and the state Supreme Court rejected an attempt to stop the execution.

In a statement to ABC News, Parson said: “No jury or court, in the trial, on appeal, or in the Supreme Court, has ever found Mr. Williams’ claims of innocence to be substantiated.”

“Ultimately, his conviction and death sentence were upheld. None of the actual facts of this case led me to believe in Mr. Williams’ innocence,” Parson added.

Williams was charged with first-degree murder in 1999 for killing 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, court documents show. After the attack, her purse and her husband’s laptop were stolen.

The kitchen knife used in the murder was found in Gayle’s body, according to court documents. Blood, hair, fingerprints and shoe prints believed to belong to the perpetrator were found throughout the house.

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

DNA evidence discovered in August revealed that the former prosecutor and the investigator who tried the original case did not wear gloves when handling the murder weapon, leaving their DNA on the knife. This revealed the source of the unidentified DNA, which did not come from an unidentified killer.

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

“None of the actual facts of this case led me to believe in Mr. Williams’ innocence,” Parson said.

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

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