The US state of Ohio ended its three-year moratorium on the death penalty Wednesday, using a new drug cocktail that included a controversial sedative to execute a convicted child murderer and rapist.
Ronald Phillips, 43, was put to death by lethal injection, the Ohio Department of Rehabilitation and Correction said. He was pronounced dead at 10:43 am (1443 GMT).
Phillips was 19 years old in 1993 when he was convicted of raping and killing three-year-old Sheila Marie Evans, his then-girlfriend's daughter.
The US Supreme Court denied a last-minute appeal late Tuesday.
The execution of Phillips comes amid waning support among the American public for the death penalty, and as fewer and fewer states carry out capital punishment.
Several states have struggled to find the drugs needed for lethal injections, as pharmaceutical companies have restricted the use of their products for executions.
Court challenges have ensued as states have tried new drug cocktails that some say result in suffering for the death row inmates -- and thereby, a violation of their constitutional protection from "cruel and unusual" punishment.
Phillips was put to death using a three-drug protocol endorsed by a federal appeals court last month that included the sedative midazolam, which lawyers for Phillips and two other inmates said did not lead to sufficient anesthetization.
The midwestern US state had halted its use of capital punishment in 2014, following the botched execution of Dennis McGuire using midazolam, during which the inmate appeared to suffer, snorting and gasping for several minutes.
In the suit filed by Phillips and his fellow inmates, a federal district judge and a three-judge appeals panel initially sided with them, saying the midazolam cocktail posed too great a risk of cruel and unusual punishment.
The state countered that its new drug protocol calls for a 50-times greater dose of the sedative, rendering it more effective. A full appellate panel agreed with Ohio, saying "the Constitution does not guarantee 'a pain-free execution.'"
Phillips's execution on Wednesday using the higher dose of midazolam was peaceful, and he did not exhibit any complications, witnesses said.
Phillips admitted to his crimes, but said his own sexual and physical abuse at the hands of his father were mitigating circumstances not considered at trial.
The state twice denied his clemency petitions.
In December 2016, on his second petition, the Ohio state parole board wrote: "Phillips's crime involved the killing of a vulnerable three-year-old victim, an abuse of trust, and extensive victimization, therefore making it among the worst of the worst capital crimes."
While the US Supreme Court refused to stay the execution on Tuesday night, Justice Sonia Sotomayor wrote in a dissent that the appellate court should have deferred to the evidence-based findings of the lower court judge.
"The Court of Appeals and this Court should not so lightly disregard those findings," Sotomayor said.
The United States has now executed 15 people in 2017, nine of them using a drug cocktail with midazolam, according to the Death Penalty Information Center.
While the death penalty is legal in a majority of US states, only 49 percent of Americans nationwide support capital punishment for murder, the lowest level of support in more than 40 years, a 2016 Pew poll found.