A Mississippi man who became the first person to be executed in the state in nearly 10 years confessed to an additional killing before his execution last month, authorities announced Monday.

David Neal Cox, 50, admitted to killing his sister-in-law, Felicia Cox, in 2007 and revealed where he buried her body, according to District Attorney John Weddle. Cox was executed for the murder of his estranged wife, Kim Cox. He was also convicted of sexually assaulting his stepdaughter multiple times.

“We would like to stress that locating the remains of Felicia Cox is not a foregone conclusion,” Weddle said at a press conference. “We are hopeful that the information is accurate and that recovery efforts will be successful so that Felicia’s family may give her a proper burial.”

MISSISSIPPI MAN BECOMES STATE'S FIRST DEATH ROW EXECUTION IN NEARLY 10 YEARS

Felicia Cox's daughter, Amber Miskelly, was present at the press conference with her husband. Miskelly was 18 at the time of her mother's disappearance. Cox had been a suspect in Felicia Cox's disappearance but was never charged in connection to it.

Mississippi's Office of Capital Post-Conviction Counsel said David Cox "felt deep remorse and wanted to bring closure" to his victim’s family, according to a news release. He waived all attorney-client privilege upon his death.

Mississippi Execution Victims
This undated photo provided by the Mississippi Department of Corrections shows David Neal Cox. The Mississippi Supreme Court has set a Nov. 17, 2021, execution date for Cox, who withdrew his appeals. He pleaded guilty in September 2012 to shooting his wife Kim in May 2010 in the town of Sherman, sexually assaulting her daughter in front of her, and watching Kim Cox die as police negotiators and relatives pleaded for her life. (Mississippi Department of Corrections via AP) AP


Authorities have not released any information on what they may have learned about how Felicia Cox was killed or where her body is believed to be located.

She was last seen in Pontotoc, Mississippi, visiting her sister-in-law, Kim, the woman David Cox was executed for killing. He killed Kim Cox three years after Felicia's disappearance in Sherman, Mississippi. He also admitted to sexually assaulting his stepdaughter, Lindsey Kirk, who was 12 at the time, including the night he killed his wife. He assaulted Kirk three times and forced her mother to watch as she was dying, according to court documents.

David Cox pleaded guilty to the murder of Kim Cox and abandoned all appeals. He also filed paperwork claiming he was "worthy of death." He was executed Nov. 17 at the Mississippi State Penitentiary.

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"I want my children to know that I love them very much and that I was a good man at one time," David Cox said just before his death, according to the Associated Press. "Don't ever read anything but the King James Bible."

Kirk was present at his execution, which the state corrections commissioner, Burl Cain, said went "picture perfect."