The US state of Missouri has halted the execution of a man who was scheduled to be put to death on Tuesday for the 1998 murder of a woman after new DNA evidence surfaced supporting his claim to innocence.

Missouri Governor Eric Greitens issued a stay of execution on Tuesday for Marcellus Williams, who was sentenced to death in 2001 for killing Lisha Gayle, a former reporter, during a burglary.

The decision came a few hours before Williams was due to be lethally injected in a state prison.

The execution of Williams, who has always maintained his innocence, was originally planned for January 28, 2015, but a court decided that DNA from the case should be investigated using techniques that were not available when the trial took place.

This test showed that the DNA on the murder weapon was not Williams'. A bloody footprint and hair fibres found at the scene of the crime also did not belong to Williams.

With no forensic or witness testimony linking Williams directly to the murder, the prosecution based its case on the testimonies of two people who later received a financial reward from the victim's family during a trial where 11 of the 12 jurors were white.

However, the court refused to take this new evidence into consideration, planning to go ahead with the execution nonetheless.

READ MORE: Marcellus Williams faces execution despite new evidence

"A sentence of death is the ultimate, permanent punishment," Greitens said in a press release on Tuesday. "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."

Kent Gipson, the lawyer of Williams, said he was "very happy" with the governor's decision.

"We think it’s the right decision based on the new DNA evidence," Gipson told Al Jazeera. "We're ready to present all our evidence to the board of inquiry, and we are fairly confident that this is going to end well for Marcellus."

READ MORE: Marcellus Williams and the US' 'broken justice system'

The Board of Inquiry appointed by the governor will consist of five former Missouri judges who will report back to Greitens with a recommendation as to whether or not Williams should be executed or his sentence of death commuted.

Staci Pratt, executive director of human rights organisation Missourians for Alternatives to the Death Penalty, who has been campaigning against the execution, also welcomed Greitens' decision.

"We have much to celebrate right now but also much to acknowledge how we got to this day that we need to hold these rallies. Our capital punishment is broken, and our judicial system still has major flaws," Pratt told Al Jazeera.

"This is a wakeup call and a siren, this is about more than just Marcellus' case. Naturally, we are happy with today's result, but we must make sure that cases like Marcellus' don't arise again."

Before Greitens' statement, more than 200,000 people had signed a petition asking for the governor's intervention.

"The voices of the people definitely mattered," Pratt said. "Naturally, we're still vigilant, we're still here to see this process and that he gets a fair inquiry by this board."

For Williams' supporters, the case was an example of the racial bias of a broken justice system. "It has a history of getting African Americans off the jury, especially when there is a white victim," Gipson said earlier to Al Jazeera, explaining that six of the seven potential black jurors were struck off the jury by the prosecution.

Rod Chapel, the head of the Missouri chapter of the National Association for the Advancement of Colored People (NAACP), said this case is about more than the life of one man; it is about a flawed and racist justice system.

"We should be concerned about the quality of our judicial system as a whole. There are still many cases that are percolating through the system where there is a feeling of injustice. There should be justice and equality for all."