Ernest Lee Johnson. (Missouri Department of Corrections via Reuters)

The Supreme Court on Tuesday night halted a scheduled execution in Missouri, saying that the lethal injection should be delayed until after a lower court rules.

Ernest Lee Johnson was sentenced to death for killing three people with a claw hammer in 1994.

Johnson’s attorneys wrote in filings asking the Supreme Court to stay the execution that Johnson had brain surgery in 2008 to remove a tumor, but that part of the tumor could not be removed. He is missing between 15 and 20 percent of his brain, the attorneys wrote. As a result, Johnson has brain damage and a doctor cited as a medical expert believes he could suffer seizures due to the lethal injection, his attorneys said. 

[An execution in Oklahoma was recently called off at the last minute]

The office of Missouri Attorney General Chris Koster argued in court filings that the execution should proceed, writing that Johnson waited too long to make his argument.

In an unsigned order, the justices said they were granting the stay request pending an appeal in the U.S. Court of Appeals for the 8th Circuit.

The complaint from Johnson “alleges that Missouri’s method of execution violates the Eighth Amendment as applied to a person with his particular medical condition,” the justices wrote.

In the order, the justices continued:

A supporting affidavit by a medical expert states that “[a]s a result of Mr. Johnson’s brain tumor, brain defect, and brain scar, a substantial risk of serious harm will occur during his execution as result of a violent seizure that may be induced by [the] Pentobarbital injection.”

They went on to say that the appeals court will have to decide whether a complaint of Johnson’s that was dismissed was properly dismissed or should have been allowed to progress.

Johnson was scheduled to be executed at 6 p.m. local time. Instead, reporters gathered to witness the execution were eventually sent home, as state officials were standing down for the night, Mike O’Connell, a spokesman for the Missouri Department of Corrections, said shortly after 10 p.m. local time.

Officials have no indication that the issue of Johnson’s appeal will be resolved on Wednesday, O’Connell said. The execution warrant for Johnson is good for 24 hours, so it expires at 5:59 p.m. on Wednesday, according to O’Connell.

This is not the first time an execution in Missouri has been called off due to concerns about whether a condemned inmate’s health could lead to unconstitutional pain and suffering during a lethal injection. Last year, the Supreme Court halted the execution of Russell Bucklew, who said he had a rare condition that could have caused suffering if he was executed.

Related:

Oklahoma pushes all executions to 2016 to investigate use of the wrong lethal drug

Oklahoma court calls off upcoming executions, Missouri governor commutes sentence of death-row inmate

This post has been updated. First published: 8:37 p.m.