Family and friends of Lyle and Erik Menendez issued a public plea for the notorious killers to be released after serving more than three decades in prison for fatally shooting their wealthy parents in their Beverly Hills home.

The Menendez brothers case became one of the most sensational criminal trials in decades when the two were arrested in the 1989 deaths of Kitty and Jose Menendez.

Family, friends and an attorney for the brothers gathered on Wednesday in front of a courthouse in Los Angeles to ask for their release, arguing that the boys endured horrific sexual abuse at the hands of their father and are not a threat to society.

But not every relative wants them released. An attorney for their uncle said the “cold-blooded” brothers deserve to stay in jail.

The back and forth comes as the Los Angeles district attorney is examining new evidence in the case about the alleged abuse and whether it could warrant a retrial or allow a lighter sentence.

“If they were the Menendez sisters, they would not be in custody,” Anna Maria Baralt, Jose Menendez’s niece, said at the packed news conference. “We have evolved.”

Ms Baralt was referring to how male victims of sexual assault were treated and considered by society and the justice system three decades ago, something prosecutors have acknowledged as well.

The brothers went to trial in 1993 and admitted to shooting their parents with a pair of shotguns, but they argued they did so out of self-defence after years of emotional, physical and sexual abuse by their father.

Prosecutors argued the brothers methodically planned their parents’ murder – as the couple watched TV – so they could inherit their multimillion estate.

The case went to a retrial after the jury deadlocked.

In the second trial in 1995, much of the evidence relating to the alleged sexual abuse was not allowed to be presented. A jury found both brothers guilty of first-degree murder and they were sentenced to life in prison without the possibility of parole.

There has been renewed public interest in the murders since a Netflix series depicting the events was released in September. And new possible evidence – an alleged letter sent by Erik to another family member that details sex abuse by his father.

Kitty Menendez’s sister, Joan Anderson VanderMolen, was helped to the podium by other family members on Wednesday afternoon to face the throng of media and a handful of supporters. At 92, she said her nephews’ actions were “tragic”.

“They were just children” who were “brutalised in the most horrific ways”.

When they stood trial, she argued, “the whole world wasn’t ready to believe that the boys could be raped, or that young men could be victims of sexual violence”.

But today, “we know better” and “a jury today would never deliver such a harsh sentence”.

But a lawyer for Kitty Menendez’s brother, Milton Andersen, said: “The Menendez brothers’ cold-blooded actions shattered their family and left a trail of grief that has persisted for decades.

“Jose was shot six times, and Kitty was shot ten times, including a shot to her face after Erik reloaded.”

Mr Andersen believes his nephews should stay in prison for their “heinous act”, said the lawyer, Kathy Cady.

Earlier this month, Los Angeles County District Attorney George Gascón held a news conference announcing his office was re-examining the case and the possibility of one of two scenarios: resentencing the brothers or giving them a retrial. His office’s findings and decision are to be released at a hearing at the end of November

Mr Gascón’s office released a statement on Wednesday evening, saying while prosecutors cannot speak publicly about the case, “please know that our office is dedicated to a thorough and fair process and is exploring every avenue available to our office to ensure justice is served”.

The family is asking Mr Gascón to recommend they be resentenced – an option that could lead them to walking free if a judge approves the order.