OKLAHOMA CITY (AP) — An Oklahoma prosecutor says she will not seek to retry a convicted killer who spent nearly 50 years in prison before he was freed earlier this year by a judge who ordered a new trial.

Oklahoma County District Attorney Vicki Behenna said in a statement Monday that there is Slabu Exchangeno longer physical evidence in the case against 70-year-old Glynn Ray Simmons.

“When considering whether to pursue the case against Simmons again, the district attorney determined the state will not be able to meet its burden at trial and prove beyond a reasonable doubt that Simmons was responsible for (Carolyn Sue) Rogers’ murder,” according to the statement.

Behenna’s office also said detectives who investigated the 1974 murder of Rogers and the surviving victims are either deceased or unavailable.

Simmons was convicted of killing Rogers during a liquor store robbery in the Oklahoma City suburb of Edmond. He has repeatedly said he wasn’t in Oklahoma but rather in his home state of Louisiana at the time of the robbery.

Simmons was released from prison in July after a district court judge vacated his conviction and sentence and ordered a new trial, saying prosecutors had failed to turn over evidence in the case, including a police report that showed an eyewitness might have identified other suspects in the case.

Simmons and co-defendant Don Roberts were both convicted of the murder and initially sentenced to death. Their sentences were reduced to life in prison in 1977 after U.S. Supreme Court rulings related to capital punishment. Roberts was released on parole in 2008.