A convicted killer will not be executed Tuesday night after Missouri Gov. Eric Greitens, a Republican, stayed the planned execution.

Greitens appointed a board to further investigate the case of Marcellus Williams, who was convicted of killing a former newspaper reporter in 1998. Williams' attorneys argued new DNA evidence proves his innocence after years of arguing for his innocence.

"A sentence of death is the ultimate, permanent punishment," Greitens said in a statement. "To carry out the death penalty, the people of Missouri must have confidence in the judgment of guilt. In light of new information, I am appointing a board of inquiry in this case."

Williams, 48, was convicted in 2001 of the brutal murder of Felia "Lisha" Gayle, who was stabbed more than 40 times with a butcher knife in her home.

Originally scheduled to be executed in 2015, the Missouri Supreme Court stayed his planned lethal injection and allowed him to get a new DNA testing that was not available during his trial two decades ago. However, the state Supreme Court denied Williams' attorney's request for a stay earlier this month, and did not provide a reason as to why.

New DNA tests, Williams' attorneys argue, show "conclusive scientific evidence that another man committed this crime."

The Missouri Attorney's General Office, however, argues that other evidence proves Williams' guilt.

"Based on the other non-DNA evidence in this case, our office is confident in Marcellus Williams' guilt and plans to move forward," said Loree Anne Paradise, deputy chief of staff for Missouri Attorney General Josh Hawley, on Monday.

Williams' execution by lethal injection would have been the 17th execution of the year in the United States, and the second in Missouri. Last year, there were only 20 executions in the U.S., the fewest in 25 years.

Missouri joins Texas and Georgia as the only three states to execute at least one inmate each year since 2013, and is one of the few states to still carry out executions nationwide.