On Friday, the city of Jacksonville, Arkansas, agreed to test DNA evidence in the case of Ledell Lee, who was put to death in 2017 after the Supreme Court voted 5–4 to allow the state to proceed with a series of executions to meet a deadline for an expiring lethal injection cocktail. Questions have swirled around Lee’s possible innocence for decades. The city’s decision clears a major hurdle in a case that could result in DNA evidence for the first time proving that a state has wrongfully executed an innocent man.

Lee was put to death for the 1993 murder of Debra Reese after Neil Gorsuch cast the tie-breaking vote to overturn the lower court injunction. It was his first vote after President Donald Trump appointed him to the Supreme Court following the nearly yearlong blockade of Judge Merrick Garland by the Republican Senate. Lee maintained his innocence until the very end of his life, and his attorneys pointed to serious issues in the case against him ahead of his execution. At the time, state courts denied requests to test DNA evidence using modern technology.

The ACLU and Innocence Project filed a lawsuit last month requesting permission to test evidence from the crime scene for the first time and presenting new forensic research that might point to Lee’s innocence. Jacksonville city attorney Stephanie Friedman initially opposed the new testing, saying she feared that if the city handed over evidence for testing it would might be “destroyed” or violate “evidence retention laws.”

On Friday, though, she agreed to allow the testing and the City Council voted unanimously to allow the city to order the testing itself, with Lee’s family paying for it. “It’s my legal opinion that we can’t release physical evidence for public inspection,” she told the City Council. “So the difference is we’re not handing over the physical evidence, we’re only getting it tested then sharing those results.”

The deal still needs to be approved by a judge—which should be a formality—but it is a critical first step in what might be a landmark case. The Innocence Project reports that 367 innocent people have been subsequently exonerated by DNA testing, including 21 death row inmates. But DNA has never been used to prove that the state has executed an innocent man or woman.

After the judge approves the deal between the city and Lee’s family, Jacksonville will send crime scene evidence to a nationally accredited lab for testing against national databases of fingerprints and DNA. That evidence includes five sets of fingerprints found at the scene of the murder, the murder weapon, scrapings from under Reese’s fingernails, a spot of blood found on Lee’s shoe that prosecutors were unable to test but claimed belonged to Reese, and hair found at the scene that prosecutors said belonged to Lee.

“This DNA and fingerprint evidence quite possibly holds the key to who killed Debra Reese in 1993,” said Cassandra Stubbs, director of the Capital Punishment Project at the ACLU in a statement. “It should have been tested before Ledell was executed. By voting to turn over the evidence for testing now, the Council members have shown that they are earnest in their pursuit of the truth and justice for the citizens of their city.”