The firing-squad execution chamber at the Utah State Prison in Draper, Utah, in June 2010. (Trent Nelson/AP)

The man known as the “ice-pick killer,” accused in a series of murders and rapes, was put to death by lethal injection in Texas on Wednesday evening following unsuccessful appeals for other execution methods that his attorneys said would be more humane for the elderly and sick prisoner.

Attorneys for Danny Bible, 66, argued that death by lethal injection would be inhumane and could result in a botched execution given Bible’s plethora of medical problems. They proposed two alternatives: death by firing squad or by nitrogen hypoxia — execution methods that are not legal in Texas but have been allowed in a handful of states.

But Bible’s legal team was unable to persuade a federal judge and the U.S. Court of Appeals for the 5th Circuit to halt his execution until state officials were able to establish new protocols for one of the proposed alternatives. Hours before Bible was executed, his attorneys asked the Supreme Court to step in. The high court denied his petition.

Bible was pronounced dead at 6:32 p.m. Central Time, the Associated Press reported. The serial rapist and child molester was sentenced to die in 2003 for raping and murdering a young wife and mother in Houston more than two decades earlier.

Despite his attorneys’ fears, Bible’s execution occurred without complications. He declined to give a final statement and stared at relatives of two of his victims who watched through a window, according to the AP. After the drugs were administered, he muttered that it was “burning” and that it “hurt.”

Bible’s attorneys said he was suffering from heart failure, coronary artery disease, chronic obstructive pulmonary disease, Parkinson’s, diabetes and several other illnesses. They argued that scars from several surgeries would make it difficult, if not impossible, to access a vein for a lethal injection. And even if the execution team managed to insert the needle, Bible’s veins were likely to rupture once doses of saline and pentobarbital begin to flow, according to a complaint filed this month in federal court in Houston.

Once Bible, who uses a wheelchair, is strapped to a gurney and lying flat, he will gasp for air and choke, attorneys argued.

But according to the AP’s account of the brief execution, prison technicians were able to insert the needles in his left and right hand. Bible died 15 minutes after the lethal dose was administered.

The Texas Attorney General’s Office, which represents state prison officials, called Bible’s request for delay “dilatory and substantively meritless” and said that although Bible’s attorneys cited problematic and botched executions in other states, no such breakdowns have occurred in Texas. The Supreme Court, the state attorney’s office argued, also should not overlook the fact that Bible had evaded justice for two decades.

“He should not be rewarded with a stay of execution simply because his evasion of authorities resulted in him reaching an older and more infirm age by the time of his execution,” the state argued.

In his ruling denying Bible’s request, U.S. District Judge Kenneth Hoyt wrote that Texas allows only one method of execution: lethal injection. Switching to one of the proposed options would require a new law and new protocol.

“Bible’s proposed alternatives are neither feasible nor readily implemented,” Hoyt wrote.

Bible was sentenced to death for the  killing of Inez Deaton, a 20-year-old wife and mother of a toddler, in Houston in 1979. Bible raped her, stabbed her 11 times with an ice pick and dragged her body to a bayou, court records say. The case was unsolved for two decades, during which Bible committed numerous violent crimes, including killing his sister-in-law, her baby and his sister-in-law’s roommate, and raping his five young nieces.

In 1998, while in custody for another rape in Louisiana, Bible confessed that he had killed Deaton, court records say.

Death by firing squad is allowed only in Utah, Oklahoma and Mississippi. Utah had avoided the method for several years, but the state reversed its policy in 2015 by making death by firing squad a backup execution method. Utah carried out the country’s most recent execution by firing squad in 2010, when the state put convicted murderer Ronnie Lee Gardner to death. That was also the last execution that Utah has carried out.

In Oklahoma, death by firing squad is a last resort if other methods were deemed unconstitutional. Mississippi joined the two states last year.

A handful of states, including Oklahoma, Mississippi and Alabama, allow execution by nitrogen hypoxia, which involves placing a condemned person in a gas chamber and depriving them of oxygen. In March, Oklahoma made an unprecedented decision to use nitrogen gas to execute death row inmates after state officials had been unable to obtain lethal-injection drugs.

Bible is the 12th man executed in the country this year.

Mark Berman contributed to this report.

Read more:

Utah governor signs bill making firing squads the state’s backup execution option

Illinois governor wants the state to revive its death penalty for mass murderers and people who kill police

Trump’s death-penalty advocacy hopes to make America 1990 again