By Dakin Andone, CNN

(CNN) — The Missouri Supreme Court has blocked an agreement that would have seen death row inmate Marcellus Williams resentenced Thursday to life without parole after new testing of DNA evidence complicated his innocence claim just over a month before he’s scheduled to be executed.

Instead, the state Supreme Court in a preliminary writ has directed the St. Louis County Circuit Court to set aside the consent judgment reached Wednesday, hold a previously scheduled evidentiary hearing and issue findings by September 13 – or explain why it should not have to. The lower court may seek an administrative stay of Williams’ execution date on September 24 while the proceedings unfold, the chief justice wrote.

The St. Louis County Circuit Court judge subsequently set the consent judgment aside and scheduled an evidentiary hearing for August 28, according to an order filed Thursday.

Williams has long maintained he did not murder Felicia Gayle, a one-time reporter for the St. Louis Post-Dispatch who was found stabbed to death in her University City home in 1998.

The consent judgment was announced Wednesday dictating Williams receive a life sentence after entering the Alford plea of guilty to first-degree murder, which generally allows a defendant to maintain their innocence while acknowledging it is not in their interest to go to trial given the evidence against them.

Missouri Attorney General Andrew Bailey, whose office said it appealed the consent judgment, praised the state Supreme Court’s ruling in a statement Thursday.

“It is in the interest of every Missourian that the rule of law is fought for and upheld – every time, without fail,” Bailey said. “I am glad the Missouri Supreme Court recognized that. We look forward to putting on evidence in a hearing like we were prepared to do yesterday.”

Tricia Rojo Bushnell, an attorney for Williams, questioned “who this decision serves or what justice it provides,” pointing out the consent judgment was reached with the support of the office that prosecuted Williams in 2001 and the victim’s family.

“We look forward to presenting the evidence that supports the circuit court’s decision at the hearing next week.”

The pivotal development leading to Wednesday’s deal was the results of new DNA testing – a report provided by the Missouri Attorney General’s Office was dated Monday, two days before this key hearing – which proved the evidence had been mishandled, complicating Williams’ innocence claim, the Associated Press reported.

The St. Louis Prosecuting Attorney’s Office, which filed a motion to vacate Williams’ conviction in January, was expected to present DNA evidence in a court hearing Wednesday that it said three DNA experts had determined excluded Williams as the wielder of the knife used to kill Gayle.

But the hearing did not get underway as scheduled, and after several hours the office of Prosecuting Attorney Wesley Bell announced the consent judgment. Bailey’s office had fought Bell’s motion, indicating in court filings Williams’ execution should proceed, and his office opposed Wednesday’s judgment, it said in a statement.

The DNA test results indicated the evidence would not exonerate Williams, Bailey said Wednesday, but show the knife had “been handled by many actors, including law enforcement,” disputing claims by the inmate’s advocates the DNA would match the true killer.

In court, Special Prosecutor Matthew Jacober, representing the St. Louis Prosecuting Attorney’s Office, acknowledged the new DNA testing showed the weapon had been mishandled by a former assistant prosecutor and an investigator, the Associated Press reported, contaminating the evidence that was supposed to support Williams’ innocence claim and making it impossible to prove someone else was the perpetrator.

Rojo Bushnell said previously Wednesday’s judgment would have ensured he remained alive “as we continue to pursue new evidence to prove, once and for all, that he is innocent.”

“The fact that there is DNA on the knife matching members of the trial prosecution team proves the State of Missouri disregarded critical protocols in the investigation of this case, including mishandling pivotal evidence,” she said. “But regardless of who may have touched the weapon between 1998 and today and deposited DNA on it, there is no doubt that Marcellus Williams did not do so.”

A copy of the judgment said it was reached after a conference Wednesday in which a representative of Gayle’s family “expressed to the Court the family’s desire that the death penalty not be carried out in this case, as well as the family’s desire for finality.”

Bell, who bested incumbent US Rep. Cori Bush in the Democratic primary for her congressional seat this month, filed the motion to vacate Williams’ conviction in January, saying the DNA evidence that could purportedly exclude Williams as Gayle’s killer had never been reviewed by a court.

“This never-before-considered evidence, when paired with the relative paucity of other, credible evidence supporting guilt, as well as additional considerations of ineffective assistance of counsel and racial discrimination in jury selection, casts inexorable doubt on Mr. Williams’s conviction and sentence,” the motion says.

Bell’s office had raised other issues with Williams’ conviction, claiming in the motion he was convicted on the testimony of two unreliable informants who were facing their own legal troubles and were further incentivized by $10,000 in reward money.