ST. LOUIS — A Missouri judge on Monday overturned the conviction of Christopher Dunn, who has spent more than 30 years in prison for a killing he has long contended he didn’t commit.

The ruling is likely to free Dunn from prison, but it wasn’t immediately clear when that would happen. He has been serving a sentence of life without parole.

St. Louis Circuit Judge Jason Sengheiser’s ruling came several weeks after he presided over a three-day hearing on Dunn’s fate.

Dunn, now 52, was convicted of first-degree murder in the 1990 shooting of 15-year-old Ricco Rogers. St. Louis Circuit Attorney Gabe Gore filed a motion in February seeking to vacate the guilty verdict. A hearing was in May.

Sengheiser, in his ruling, wrote that the “Circuit Attorney has made a clear and convincing showing of ‘actual innocence’ that undermines the basis for Dunn’s convictions because in light of new evidence, no juror, acting reasonably, would have voted to find Dunn guilty of these crimes beyond a reasonable doubt.”

Dunn’s attorney, Midwest Innocence Project Executive Director Tricia Rojo Bushnell, said she was “overjoyed” by the judge’s ruling.

“Now, Chris looks forward to spending time with his wife and family as a free man,” Bushnell said in a statement.

The Missouri Attorney General’s Office opposed the effort to vacate Dunn’s conviction. Lawyers for the state said at the May hearing that initial testimony from two boys at the scene who identified Dunn as the shooter was correct, even though they later recanted as adults.

“That verdict was accurate, and that verdict should stand,” Assistant Attorney General Tristin Estep said at the hearing.

Spokesperson Madeline Sieren said the Attorney General’s Office will appeal.

The decision in Dunn’s case came days after Sandra Hemme was freed from a western Missouri prison after serving 43 years for a murder that a judge determined she didn’t commit. Bailey’s office also opposed Hemme’s release.