After serving in prison for 12 years, 45-year-old Robert Sparks finally takes his last charge—execution. The Texas inmate was executed by lethal injection Wednesday night, Sept. 25, for fatally stabbing his two stepsons in their Dallas home.

As the lethal dose of pentobarbital began, he said, “I love you all” and then added, “I feel it.”

He took two deep breaths almost immediately, snored three times and then all movement ceased. He was pronounced dead 23 minutes later, at 6:39 p.m. CDT, according to Yahoo News

Prosecutors said in September 2007, Sparks stabbed his wife, 30-year-old Chare Agnew, 18 times as she lay in her bed. He then took his two stepsons, 9-year-old Harold Sublet and 10-year-old Raekwon Agnew, into the kitchen, separately, to stab them. Raekwon was stabbed at least 45 times. Authorities said Sparks then raped his 12- and 14-year-old stepdaughters.

After his arrest, Sparks told the police his crime was due to his belief that the victims were trying to poison him. Sparks told a psychologist that a voice told him “to kill them because they were trying to kill me.”

His attorneys asked to stop the lethal injection for the reason that a bailiff wore a tie with an image of a syringe that showed his support for the death penalty, which improperly influenced his trial jury. Justice Sonia Sotomayor wrote in the ruling she didn’t disagree with the denial, but found the bailiff’s actions “deeply troubling.”

Sparks also had alleged a prosecution witness at his trial provided false testimony regarding his prison classification if a jury chose life without parole rather than a death sentence.

The 5th U.S. Circuit Court of Appeals on Tuesday, Sept. 24, declined the proposal, saying his attorneys had not presented sufficient evidence to show Sparks was mentally disabled and had failed to raise such a claim in a timely manner.

The Texas Attorney General’s Office, which called the killings “monstrous crimes,” said in court documents that Sparks’s “own trial expert testified that he was not intellectually disabled.”

“Sparks committed a heinous crime, which resulted in the murders of two young children. He is unable to overcome the overwhelming testimony” in his case, the attorney general’s office said in its court filing with the Supreme Court.

Sparks became the 16th inmate put to death this year in the United States and the seventh in Texas. Seven more executions are scheduled in Texas this year.