David Neal Cox Sr. was born on November 30, 1970, in Mississippi. Growing up in a southern state, David's early life details are not widely recorded. As an adult, he became a truck driver. This job allowed him to travel and provided a steady income for his family.

David married Kim, and together they had two sons. Kim also had a daughter from a previous relationship, who became David's stepdaughter. The family structure was complex, with David taking on the role of a stepfather.

In August 2009, serious allegations arose against David. His stepdaughter reported him to the police, claiming that he had been sexually abusive towards her. Following these accusations, law enforcement arrested David on multiple charges. These included statutory rape, sexual battery, child abuse, and possession of methamphetamine among others.

During the time leading up to his arrest, David was facing major personal issues. He struggled to remain a stable presence for his family. He spent time in jail before posting bond, and according to reports, he expressed anger towards Kim, blaming her for his situation. This tension put a strain on their relationship, causing Kim to move in with her sister to protect herself and the children.

During the time he spent in jail, David Neal Cox became angry and blamed his wife, Kim Cox, for his situation. He declared to his cellmates that he would kill her once he was out. To keep safe, Kim and her children moved in with her sister in Sherman, Mississippi. After posting bail in April 2010, Cox confronted Kim on May 14, 2010. He bought a .40 caliber handgun and drove to his wife's sister's home.

After breaking into the house, Cox threatened Kim, her sister, his two sons, and his stepdaughter at gunpoint. He fired his weapon inside the house, causing panic. Kim’s sister and one of his sons fled, but Cox managed to take Kim, his other son, and stepdaughter hostage for more than eight hours. During this standoff, he shot Kim in the abdomen and sexually assaulted his stepdaughter multiple times. Cox refused pleas from family members and authorities to let Kim go for medical treatment, stating he wanted to see her suffer. The situation ended when the SWAT team raided the house in the early hours of May 15.

Cox was arrested and faced a total of eight charges. These included capital murder for killing Kim, two counts of kidnapping, one count of burglary, one count of firing into a dwelling, and three counts of sexual battery. On September 17, 2012, a jury trial began, where Cox pleaded guilty to all charges. The jury recommended the death penalty for him. He also received additional long sentences for his other crimes, totaling 185 years in prison.

Cox's appeals against his death sentence were rejected multiple times. In July 2018, he admitted in a letter his guilt for killing Kim and expressed that he would do it again if given the chance. He chose to waive his appeals and pushed for his execution. A competency hearing took place in February 2021, during which the judge confirmed that Cox understood his decision. Following this, a death warrant was issued for his execution on November 17, 2021.

On the day of his execution, Cox made a final statement, expressing love for his children and mentioning that he had once been a good man. He was executed by lethal injection at the Mississippi State Penitentiary. Before his execution, he confessed to killing his sister-in-law, Felicia Cox, who had gone missing in 2007. He indicated where her body was buried, and authorities later confirmed the identity of her remains in December 2021.