ST. LOUIS — Convicted killers in three states were facing executions within a 24-hour period starting Tuesday night, marking the first lethal injections in the nation since a botched execution in Oklahoma seven weeks ago.

All the states planning lethal injections — Florida, Georgia and Missouri — refuse to say where they get their drugs, or if they are tested. Lawyers for the condemned inmates have challenged the secretive process used by some states to obtain lethal injection drugs from unidentified, loosely regulated compounding pharmacies.

Nine executions nationwide have been stayed or postponed since late April, when Oklahoma prison officials halted the execution of Clayton Lockett after noting that the lethal injection drugs weren’t being administered into his vein properly. Lockett’s punishment was halted and he died of a heart attack several minutes later.

“I think after Clayton Lockett’s execution everyone is going to be watching very closely,” Fordham University School of Law professor Deborah Denno, a death penalty expert, said of this week’s executions. “The scrutiny is going to be even closer.”

Marcus Wellons is set to die Tuesday night in Georgia, followed six hours later by John Winfield, who faces execution at 12:01 a.m. Wednesday in Missouri. John Ruthell Henry’s execution is scheduled for 6 p.m. Wednesday in Florida.

Georgia and Missouri both use the single drug pentobarbital, a sedative. Florida uses a three-drug combination of midazolam hydrochloride, vecuronium bromide and potassium chloride.

Despite concerns about the drugs and how they are obtained, death penalty supporters say all three convicted killers are getting what they deserve.

Wellons was convicted in the 1989 rape and murder of India Roberts, his 15-year-old neighbor in suburban Atlanta. Soon after the girl left for school, another neighbor heard muffled screams from the apartment where Wellons was living. Later that day, a man told police he saw a man carrying what appeared to be a body in a sheet. Police found the girl’s body in a wooded area. She had been strangled and raped.

The Georgia State Board of Pardons and Paroles on Monday denied clemency to Wellons, leaving his fate in the hands of the courts.

In Missouri, Winfield had been dating Carmelita Donald on and off for several years and fathered two of her children. Donald began dating another man. One night in 1996, in a jealous rage, Winfield showed up outside Donald’s apartment in St. Louis County and confronted her, along with two friends of hers.

Winfield shot all three women in the head. Arthea Sanders and Shawnee Murphy died. Donald survived but was blinded.

Symone Winfield, the daughter of Donald and John Winfield, is among those asking Gov. Jay Nixon for clemency. A federal judge granted a stay of execution last week on a claim that a prison worker dropped plans to write a letter in support of clemency due to intimidation from staff. A three-judge panel of the 8th U.S. Circuit Court of Appeals late Monday upheld the stay, and the state appealed for a hearing before the full 8th Circuit.

In Florida, the state is moving ahead with the execution despite claims that Henry is mentally ill and intellectually disabled. The state claims anyone with an IQ of at least 70 is not mentally disabled; testing has shown Henry’s IQ at 78, though his lawyers say it should be re-evaluated.

Henry stabbed his estranged wife, Suzanne Henry, to death a few days before Christmas in 1985. Hours later, he killed her 5-year-old son from a previous relationship. Henry had previously pleaded no contest to second-degree murder for fatally stabbing his common-law wife, Patricia Roddy, in 1976, and was on parole when Suzanne Henry and the boy were killed.

Asked Tuesday if he had discussed with the Department of Corrections what happened in Oklahoma and if any changes were needed in Florida, Gov. Rick Scott said, “I focus on making sure that we do things the right way here.”

Florida and Missouri trail only Texas as the most active death penalty states. Texas has carried out seven executions. Florida has executed five men in 2014 and Missouri has executed four. Combined, the three states have performed 16 of the 20 executions this year.

Wellons would be the first Georgia inmate executed since February 2013 and just the second since 2011.

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