Inmate executed by lethal injection for 1998 murder of delivery driver

An Alabama inmate was executed by lethal injection on Thursday evening, the state's attorney general confirmed, marking the state's third execution this year.

Keith Edmund Gavin, 64, was convicted on two counts of capital murder in the March 1998 fatal shooting of William Clayton Jr., a delivery driver who was sitting outside a bank in his van. Clayton had stopped at an ATM for cash to take his wife to dinner.

Gavin had previously been convicted of murder -- serving 17 years of a 34-year sentence before being released on parole -- and attempted murder for shooting at a law enforcement officer, according to court documents, explaining why his charge was elevated to capital murder.

In a 10-2 vote, a jury recommended that Gavin be sentenced to death for his capital murder convictions, and a trial court accepted the jury's recommendation.

Gavin's execution date was set by Gov. Kay Ivey at the end of April. Gavin filed a motion on July 12 to stay the execution, which was denied on Tuesday.

In a lawsuit filed earlier this year, Gavin asked state officials not to conduct an autopsy on his body after the execution due to his religious beliefs, which the Alabama Department of Corrections agreed to.

"Mr. Gavin is a devout Muslim," the lawsuit read, according to AL.com. "His religion teaches that the human body is a sacred temple, which must be kept whole. As a result, Mr. Gavin sincerely believes that an autopsy would desecrate his body and violate the sanctity of keeping his human body intact. Based on his faith, Mr. Gavin is fiercely opposed to an autopsy being performed on his body after his execution."

Grant Alexander Premo, Gavin's attorney, did not immediately return ABC News' request for comment.

Lethal injection has been the method used for most executions in the modern era, according to the Death Penalty Information Center (DPIC), a nonprofit that provides data and analysis on capital punishment.

States and jurisdictions can use a one-, two- or three-drug combination. The three-drug combination involves an anesthetic or sedative then a drug to paralyze the prisoner and a drug to stop the heart, the DPIC said.

Problems have arisen with lethal injections in the form of botched executions. Officials have struggled to find veins, intravenous lines have clogged with the deadly chemicals and prisoners have had violent reactions to the dispensed drugs. Additionally, there have been shortages of the drugs used for lethal injection.

Alabama recently authorized the use of nitrogen gas for executions. In January, Kenneth Eugene Smith became the first inmate to be executed with this new method.

Alabama's second execution this year took place in May, when Jamie Ray Mills was put to death by lethal injection. Alan Eugene Miller, another inmate, is set to be executed by nitrogen gas in September.