The high court’s announcement Friday of Michael Taylor’s lethal injection date comes almost 23 years after he was sentenced for first-degree murder. Taylor and Roderick Nunley were charged with kidnapping Ann Harrison as she waited for a school bus near her home. She was raped, stabbed and left bleeding to death in the trunk of a car.

Taylor was hours away from being executed in 2006 when the procedure was halted. The U.S. Supreme Court stopped his execution and said the state’s three-drug lethal injection mixture could constitute a cruel and unusual punishment if used incorrectly.

Missouri now uses one drug for lethal injections, but that has also brought on legal challenges.

Nunley and Taylor pleaded guilty to killing the teenager in 1991 and chose to be sentenced by a Jackson County judge who had never sentenced anyone to be executed. Nonetheless, they received the death penalty. The state Supreme Court ordered new sentencing in 1993, and both received the death penalty from a different judge.

Their death sentences have been upheld through numerous appeals since then. Taylor’s attorney, John William Simon, said Friday that scheduling the execution is “highly premature in light of the lethal injection litigation that we have ongoing.”

Simon said Taylor is part of a lawsuit in federal court along with several other Missouri death row inmates challenging the state’s current execution method.

Missouri and other states used a three-drug execution method for decades, but pharmaceutical companies have stopped selling those drugs for use in executions. Many states now get the drugs from compounding pharmacies, which custom mix drugs for individual clients. Unlike typical pharmaceutical firms, compounding pharmacies are not regulated by the U.S. Food and Drug Administration, though they are subject to state regulations.

The planned Wednesday execution of Herbert Smulls, who was convicted of killing a St. Louis County jeweler in 1991, would be Missouri’s third lethal injection using pentobarbital, a powerful sedative.

Nunley was scheduled to be executed in 2010, but was granted a stay.