(Adds details on execution)
KANSAS CITY, Mo., Jan 30 (Reuters) - Missouri late on Wednesday executed a man convicted of killing a jewelry store owner during a robbery after the U.S. Supreme Court denied last-minute appeals that in part challenged the drug used in the execution.
Herbert Smulls was pronounced dead at 10:20 p.m. local time at a state prison in Bonne Terre after receiving a lethal dose of pentobarbital, a fast-acting barbiturate, Missouri Department of Corrections spokesman Mike O'Connell said.
Smulls, 56, did not make a final statement, but asked which way he should look from the gurney to see his witnesses and nodded at them before being declared dead nine minutes after being injected with the drug, O'Connell said.
Smulls was the sixth person executed in the United States in 2014 and the third in Missouri since November.
The U.S. Supreme Court on Wednesday lifted a temporary stay of execution for Smulls, denying last-minute appeals. The top court late Wednesday also vacated a stay from the Eighth Circuit U.S. Court of Appeals that had prevented the execution.
Lawyers for Smulls filed another request with the Supreme Court on Wednesday evening, but Missouri went ahead with the execution before the midnight expiration of the state's death warrant.
O'Connell said the state followed procedures to ensure it was clear of all legal impediments to the execution. Lawyers for Smulls did not respond to requests for comment.
Smulls was convicted of shooting Stephen Honickman while robbing his jewelry store in July 1991. Honickman's wife Florence, who was also shot during the attack, sustained permanent injuries.
Smulls was originally scheduled to die after 12:01 a.m. Central Time on Wednesday and so had his final meal of fried chicken, steak, collard greens, macaroni and cheese, candied yams, corn bread, chocolate cake, and cola on Tuesday afternoon.
Lawyers for Smulls had sought to block his execution on multiple grounds, arguing in part that the compound drug Missouri used to kill him might not be as pure and as potent as it should be, which could cause undue suffering.
Missouri and several other states have turned to compounding pharmacies, which are not regulated by the U.S. Food and Drug Administration, to prepare drugs for executions after an increasing number of pharmaceutical manufacturers objected to their drugs being used in capital punishment.
The increasing use of in some cases untested compounded drugs has revived the debate over the death penalty in the United States.
In Oklahoma, an inmate said he felt burning through his body when the drugs used to kill him were injected during an execution in early January. Later in the month, an Ohio man gasped and convulsed during his execution with a two-drug mix never before used in the United States.
In the Smulls case, the Eighth Circuit U.S. Court of Appeals found on Friday that his lawyers did not propose a feasible or more humane alternative than pentobarbital or showed that Missouri sought to cause him unnecessary pain by using the drug.
The Eighth Circuit had separately granted a stay until the U.S. Supreme Court decided whether to hear the case.
The Supreme Court granted Smulls the temporary stay late Tuesday, hours before his execution was to be carried out, to consider his lawyer's arguments that prosecutors had improperly eliminated a black woman as a possible juror, leaving him with an all-white jury at trial.
On Wednesday afternoon, the Supreme Court vacated the temporary stay and denied the request for a stay or to hear the appeal on the jury selection issue. (Reporting by Carey Gillam and Kevin Murphy in Kansas City, Lawrence Hurley in Washington, and Heide Brandes in Oklahoma City; Writing by David Bailey and Eric M. Johnson; Editing by Eric Walsh, John Stonestreet)