LOS ANGELES — A Los Angeles Superior Court judge on Monday rejected a request for a new trial for Erik and Lyle Menendez, closing another legal avenue for the brothers who have spent decades behind bars for the 1989 slayings of their parents.

Judge William C. Ryan denied a May 2023 petition that sought review of the brothers' 1996 convictions on the basis of newly presented evidence that their defense says supports allegations of sexual abuse by their father. In a written ruling, Ryan said the new material "slightly corroborates" the brothers' claims but does not negate that the killings were carried out with "premeditation and deliberation."

Ryan wrote that the evidence alleged "is not so compelling that it would have produced a reasonable doubt in the mind of at least one juror or supportive of an imperfect self-defense instruction." Defense lawyers had argued the brothers acted in self-defense after years of sexual abuse by their father, Jose Menendez. Prosecutors have maintained the siblings killed their parents to secure a multimillion-dollar inheritance.

The decision comes weeks after parole commissioners denied both brothers short-term release, marking the closest they have come to freedom since their convictions. Lyle Menendez was denied parole for three years after an Aug. 22 hearing where commissioners cited what they described as "anti-social personality traits like deception, minimization and rule-breaking that lie beneath that positive surface." Erik Menendez was denied parole a day earlier after commissioners pointed to disciplinary misbehavior in custody and said he remained a risk to public safety.

Erik and Lyle Menendez were convicted in 1996 of fatally shooting their parents, Jose and Kitty Menendez, at the family's Beverly Hills home on Aug. 20, 1989. Both were sentenced to life in prison. A judge reduced their sentences in May, making them immediately eligible for parole and setting the stage for the hearings held this summer.

Attorneys for the brothers argued that newly discovered evidence undermines the prosecution's theory and supports a narrative of prolonged abuse that would have been central to jurors' consideration of motive and culpability. Ryan's ruling reiterated the stringent legal standard for granting a new trial based on new evidence: the evidence must be so compelling that it probably would have produced a different outcome at trial.

An email was sent to Mark Geragos, a lawyer for the Menendez brothers, seeking comment on the ruling. Prosecutors in the original case have long maintained that the killings were planned and motivated by financial gain.

The ruling removes a judicial path the defense had pursued after decades of appeals and litigation. With the denial of the petition and recent parole decisions, the Menendez brothers remain in state prison, where they have served nearly four decades for the murders that drew intense media attention and public scrutiny.

The criminal case has remained a fixture in public discourse about high-profile killings, family dynamics and the intersection of alleged abuse and criminal responsibility. Legal experts say the decision underscores the high bar defendants face when seeking new trials on the basis of evidence that postdates conviction and trial proceedings.

No immediate steps by the defense to challenge Ryan's ruling were disclosed Monday.