A man who killed his estranged wife and terrorized their family has expressed some remorse for the 2010 attack ahead of his scheduled Wednesday evening execution, the head of the Mississippi prison system said.

Corrections Commissioner Burl Cain told reporters that David Neal Cox, 50, has been calm and “upbeat” in the days before his expected execution, which was scheduled after he surrendered all appeals. Cox pleaded guilty to capital murder and other charges two years after the attack. He has filed court papers calling himself “worthy of death.”

Cain did not elaborate on how Cox has been upbeat, but he said the inmate has been speaking with a spiritual adviser and with prison officials.

“It’s obvious, you know, that he made a lot of bad decisions,” Cain said Wednesday at the prison. “And I think he qualified it best by saying, ‘I wasn’t always that bad.’”

Cox was scheduled to receive a lethal injection at 6 p.m. CST. It would be Mississippi’s first execution since 2012.

Prosecutors said Cox shot Kim Kirk Cox and let her bleed to death over several hours while he sexually assaulted his 12-year-old stepdaughter three times in front of her dying mother.

Mississippi and other states have had difficulty finding lethal injection drugs because pharmaceutical companies began blocking their use to carry out death sentences.

The Mississippi Department of Corrections revealed in court papers earlier this year that it had acquired three drugs for the lethal injection protocol: midazolam, which is a sedative; vecuronium bromide, which paralyzes the muscles; and potassium chloride, which stops the heart.

Cain told The Associated Press on Tuesday that the drugs listed in the court records are the ones planned for Wednesday’s execution. He declined to identify their source.

Republican Gov. Tate Reeves has no intention of granting clemency or delaying the execution, his spokeswoman said. Death Penalty Action, which opposes executions, petitioned Reeves to step in, saying that executing someone who waived appeals “amounts to state-sponsored suicide.”

Attorneys from the Mississippi Office of Capital Post-Conviction Counsel represented Cox in recent years. After the state Supreme Court set his execution date, Cox sent a handwritten statement strongly objecting to their continued involvement. The office director, Krissy C. Nobile, said Tuesday that after “considerable and difficult deliberation, and out of respect for David Cox’s autonomy and stated desire,” the office did not plan any more appeals for him.

Mississippi carried out six executions in 2012. The state has no others scheduled though more than 30 people are on its death row.

Cox pleaded guilty in 2012 to capital murder in the shooting death of his wife. He also pleaded guilty to multiple other charges, including sexual assault. A jury handed down the death sentence.

Among those scheduled to witness the execution were Cox’s stepdaughter, 23-year-old Lindsey Kirk. She was 12 when he sexually assaulted her in front of her mortally wounded mother as he held them and one of her younger brothers hostage on May 14 and May 15, 2010, in a house in the small town of Sherman.

Kim Cox’s father, retired law enforcement officer Benny Kirk, described David Cox as “evil.” Benny Kirk said David Cox called during that night and said he had shot Kim. Benny Kirk spoke on the phone with his daughter and she told him: “’Daddy, I’m dying.’”

Police surrounded the house and tried to get David Cox to release his wife and the two children. Kim Cox was dead by the time the ordeal ended after more than eight hours.

The Associated Press does not usually identify victims of sexual assault, but Lindsey Kirk agreed to be interviewed and talk about what happened to her. She told the AP last week that David Cox had sexually assaulted her for several years when her mother was out of the house, and that he threatened to kill them if she told anyone.

While staying with her grandparents in the summer of 2009, Kirk texted her mother and told her of the assaults by her stepfather. Soon after that, David Cox was arrested and charged with statutory rape, sexual battery, child abuse and possession of methamphetamine. He was released in April 2010 without standing trial. Kim Cox obtained a restraining order against him and moved with her children to her sister’s home.

Questions remain about whether David Cox was responsible for the 2007 disappearance of his brother’s wife, Felicia Cox, who was last seen in a neighboring county. Her daughter, Amber Miskelly, recently told WTVA-TV that David Cox was the last person to see her mother alive. Felicia Cox’s body was never found, and no one has been charged in her disappearance.

Cain said Wednesday that David Cox has not discussed the disappearance of his sister-in-law.