The Supreme Court on Wednesday declined to block the execution of a man on death row in Florida after he argued that his death sentence was unconstitutional.

Donald Dillbeck, who was found guilty of first-degree murder in 1990, applied to the court for a stay of the execution and petitioned for a writ of certiorari, or review of the case, raising constitutional questions. The Supreme Court denied both.

Florida Gov. Ron DeSantis (R) signed the death warrant for Dillbeck last month, and Dillbeck’s petition for a stay at the state level was denied.

Dillbeck was convicted of killing a woman in Tallahassee after he had escaped from custody while serving a separate life sentence for killing a deputy in 1979, according to the filing from the state of Florida. 

His attorneys argued that Dillbeck was entitled to an exemption from execution because of a neurobehavioral disorder associated with Prenatal Alcohol Exposure. They also asked the Supreme Court to weigh in on whether the Eighth Amendment requires a death sentence to be recommended by a unanimous jury — Dillbeck was sentenced in an 8-4 decision.

At the time he was sentenced, Florida required only a simple majority of the jury to recommend the death penalty. The threshold was raised to a unanimous jury in 2017 following a Supreme Court decision striking down part of the state’s capital punishment system.

Earlier this month, DeSantis proposed legislation to again update the state’s death penalty statute and bring down the bar for a death sentence to a supermajority.

Dillbeck’s execution by lethal injection has been scheduled for Feb. 23 at 6 p.m. in Florida.