Cooper Koch, who plays Erik Menendez in Monsters: The Lyle And Erik Menendez Story told Sky News: "I totally stand with them, and I support them, and I can only hope that the justice system makes the right decision."

The brothers were convicted of shooting their father and mother Jose and Mary Louise "Kitty" Menendez multiple times at close range in the family mansion in Beverly Hills, California, on 20 August 1989. They were 21 and 18 at the time.

During their trial, the defence claimed the brothers committed the murders in self-defence after many years of alleged physical, emotional and sexual abuse.

The prosecution argued the murders were motivated by greed, and said the brothers killed their parents to avoid disinheritance.

While an initial trial of each brother separately ended in a mistrial, a second joint trial saw them convicted of first-degree murder and conspiracy to murder and sentenced to life imprisonment without the possibility of parole.

The day after the Netflix drama aired, Erik Menendez put out a scathing statement about the show via his wife Tammi, calling it "dishonest" and "inaccurate".

Responding to his criticism, Koch, who recently visited the brothers with Kim Kardashian, said: "I understand where he's coming from. It's very difficult to have your life dramatized and retold in a Hollywood retelling of the biggest trauma of your life. One that has, in a sense, defined you.

"I can only sympathise and empathise with him and stand with him. You know, I get it."

No 'battle' with ethical issues

In drawing a line between fact and fiction, the 28-year-old actor said: "I definitely think there's an ethical thing there for sure. Nothing that I battled with.

"I just made it my priority every day to make sure that I was being authentic to [Erik] and the story and to just work with integrity and make sure that I was always studying and watching testimony and just digging deeper and deeper into, him and his story."

He said having Erik's own words from court made his job as an actor easier: "I don't really have to use a tonne of my imagination. It's like he's telling me, and all I have to do is visualise what happened and the stories that he recounts on the stand.

"In that sense, it kind of makes the job... It's like you have this blueprint already. You don't have to create from a blank canvas."

Erik's 'still in prison sadly'

He said one thing that made the job "a little bit more difficult".

"There is the pressure that he is a real person, and he is still alive. And he is still in prison, sadly. That's why I made sure that every day I was thinking about him and I made it my utmost priority to just be as authentic as possible."

Actor Nicholas Alexander Chavez, who plays older brother Lyle in the show, told Sky News there was "an enormous weight involved with playing a real person".

Chavez said after "extensive research", and in collaboration with the creative vision of the directors and showrunners, "what ends up on screen is art".

As for the accuracy of the portrayal, Chavez said: "We all want it to be as respectful as possible."

Visiting jail with Kim Kardashian

Koch recently visited the brothers at San Diego County's Richard J Donovan Correctional Facility, where both brothers are being held, alongside Kim Kardashian.

He called the visit "a very rewarding experience," and that Kardashian, who has been training to be a lawyer since 2019, was "super passionate" about criminal reform.

Koch said their visit was inspired by Lyle and Erik's spearheading of a green space project - Greenspace - which aims to improve the appearance of prison yards to assist with rehabilitation.

He explained they hope to "make it feel less grey and cold… and help these incarcerated individuals feel like they can have a purpose and meaning in their life in prison".

Koch said the experience of working on the Ryan Murphy show had "definitely changed my life".

Possibility of a retrial?

The original trial of the Menendez brothers in 1993 was a media sensation, televised for Court TV, and a talking point across America.

The joint trial two years later, at which evidence of the brothers' alleged sexual abuse at the hands of their father was ruled inadmissible.

After their sentencing in 1996, the brothers did not see each other for 22 years, serving time in different jails until 2018 when Erik was moved to same facility as Lyle. They are now aged 53 and 56 respectively.

Over the last few years interest in the case has spiked, with a growing TikTok movement to free the brothers.

The Netflix drama, and a forthcoming documentary coming to the streamer in October, has only added to growing speculation over the case.

Now, recent new evidence, which surfaced in the 2023 documentary Menendez + Menudo: Boys Betrayed has led to calls for a retrial.

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The film featured claims from former Puerto Rican boyband member Roy Rossello, who alleged Jose Menendez sexually assaulted him when he was a teenager.

The brothers' defence team also say they've uncovered a letter that Erik Menendez had written to his cousin that was dated months before the murders, where he talked about what he said was abuse from his father and being afraid of him.

The defence team say this should warrant a new trial because it's information they didn't have when the case was first presented to a jury.

The LA county's district attorney's office told Sky News' US partner NBC News they are investigating the claims and will have a response by 26 September.