A death row inmate has been executed for killing his wife and stepsons before raping his stepdaughters.
He then went into the bedroom of nine-year-old Harold Sublet and 10-year-old Raekwon Agnew and took them into the kitchen separately, where he stabbed them.
Raekwon was stabbed at least 45 times.
Sparks then raped his 12- and 14-year-old stepdaughters, authorities said.
He locked his stepdaughters in a cupboard and left the home, stopping at his mother’s house to borrow her car, and then his ex-girlfriend’s home, where he told her he had killed his wife and two stepsons.
On arrest, he told police his wife had been poisoning him.
He provided blood, hair and fingernail samples, as well as a cheek swab, to be tested for evidence of poisoning, but investigators were unable to find a lab capable of that type of test, according to court papers.
He also told a psychologist that a voice told him “to kill them because they were trying to kill me”.
As relatives and friends watched through a death chamber window, Sparks told them: “I am sorry for the hard times. And what hurts me is that I hurt y’all.”
Speaking after his death, one of Sparks’ stepdaughters said: “The day when the situation was going on, he said that we wouldn't make it.
“Twelve years later, we’re both standing here... I want him to know we’re not suffering. We’re hurt emotionally but physically we’re fine.”
Sparks’ lawyers had argued he suffered from severe mental illness and had been diagnosed as a delusional psychotic and with schizoaffective disorder.
They also claimed he was intellectually disabled and was therefore not eligible for the death penalty, however the 5th US Circuit of Appeals on Tuesday declined to stop the execution on these grounds.
Sparks also argued that a prosecution expert gave false testimony and that the trial jury may have been influenced by a bailiff who wore a tie with an image of a syringe which showed his support for the death penalty.
Sparks is the 16th inmate in the United States and the seventh in Texas to be executed in 2019, according to the Death Penalty Information Centre.
Texas has executed more prisoners than any other state since the Supreme Court reinstated capital punishment in 1976.
Agencies contributed to this report.
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