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The final words of a killer could provide clues that may solve an unexplained disappearance, according to a witness to his execution.
50-year-old David Neal Cox was put to death in Mississippi on Wednesday evening having been sentenced to death in 2012 for the killing of his estranged wife Kim Cox, who he kidnapped and shot before sexually assaulting her daughter in front of her as she died.
Before he died from lethal injection at the state penitentiary, he spoke his final words, which were heard by Burl Cain, the commissioner of the Mississippi Department of Corrections.
According to Cain, he said: "I want to tell my children that I love them very, very much and that I was a good man at one time."
However, he also reported that Cox spoke of a letter that will be mailed after he died regarding the disappearance and suspected murder of Felicia Cox, his sister-in-law.
She went missing in 2007 and it has long been suspected that her brother-in-law had something to do with it.
He was the last person to see her alive, and her family had long hoped that he might provide the evidence and closure that they need in finding out what actually happened to her.
So, as he was about to die, Cox revealed that the letter had been left with someone - we don't yet know who - and said that it would be mailed after his execution had taken place.
Felicia's body has never been found.
The execution comes after Cox was convicted of Kim's murder, having been reported in 2009 by his then-wife for sexually assaulting her daughter from a previous relationship.
In May 2010 he broke into her house with a gun and took her and her children hostage for eight hours, eventually shooting his wife in the stomach and arm.
During the long police standoff, he assaulted her daughter several times and denied Kim medical treatment.
He even forced her to beg for her life on the phone to negotiators and her parents.
Cox pleaded guilty to eight counts, including capital murder and sexual assault, for which he was given the death penalty.
Before his execution, he asked the Mississippi Supreme Court to stop any appeals that could have halted his execution.
In 2018, he wrote a letter to the court's chief justice, arguing that he was 'a guilty man worthy of death'.
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