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A Mississippi man who was executed last month for fatally shooting his estranged wife confessed to another killing just before he died, a prosecutor revealed Monday.

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David Neal Cox, 50, told his lawyers he killed his sister-in-law, Felicia Cox, in 2007 and provided detailed instructions on where her body could be found, John Weddle disclosed at a press conference. He is the DA of several northern Mississippi counties.

Mississippi inmate David Neal Cox

This undated photo provided by the Mississippi Department of Corrections shows David Neal Cox. (Mississippi Department of Corrections via AP) (Mississippi Department of Corrections via AP)

Cox made the stunning admission to his lawyers before he received a lethal injection on Nov. 17 — marking the first execution in the state in nine years.

Felicia’s daughter, Amber Miskelly, who was just 18 when her mom vanished in July 2007, was present at the news conference. She stood beside her husband silently, wiping away tears, as Weddle spoke. Authorities said they plan to try to recover the body but did not disclose its exact location.

The state’s Office of Capital Post-Conviction Counsel, who represented Cox, said he "felt deep remorse and wanted to bring closure" to his victim’s family.

Lindsey Kirk

Lindsey Kirk looks at childhood photographs of herself and her late mother Kim Kirk Cox, Saturday, Nov. 13, 2021, in New Albany, Miss. She was 12 years old when her stepfather, David Neal Cox, terrorized her family, sexually assaulted her, and killed her mother, Kim Kirk Cox, in May 2010 at a home in Sherman, Miss. (AP Photo/Rogelio V. Solis) ((AP Photo/Rogelio V. Solis))

Felicia, 40, was last seen visiting her sister-in-law Kim Kirk Cox, in Pontotoc — 30 minutes east of the college town of Oxford.

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Three years later, Cox shot dead his wife, Kim, the crime for which he was executed.

After the shooting, Cox called his wife’s father, Benny Kirk, and let him speak to her. "Daddy, I’m dying," she whimpered.

Lindsey Kirk shows childhood photographs of herself and her late mother Kim Kirk Cox

Lindsey Kirk shows childhood photographs of herself and her late mother Kim Kirk Cox, Saturday, Nov. 13, 2021, in New Albany, Miss. She was 12 years old when her stepfather, David Neal Cox, terrorized her family, sexually assaulted her, and killed her mother, Kim Kirk Cox, in May 2010 at a home in Sherman, Miss.  (AP Photo/Rogelio V. Solis) (AP Photo/Rogelio V. Solis)

Police surrounded the house and tried to get Cox to release his wife and the two children inside, his stepdaughter Lindsey Kirk, then 12, and her little brother. As Kim lay dying from a gunshot wound, David Cox sexually assaulted his stepdaughter three times. The standoff lasted eight hours and by then Kim was dead and her children deeply traumatized.

Cox pleaded guilty to capital murder and other charges in 2012, and a jury handed down the death sentence.

He did not fight the verdict and filed court papers calling himself "worthy of death."

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Lindsey Kirk, now 23, who has shared her name publicly, attended the execution of her abuser and her mother’s killer.

Before David Cox took his final breath, he said, "I want my children to know that I love them very much and that I was a good man at one time."

Associated Press contributed to this report.