The Reiner family has been publicly united in grief since the brutal killings of legendary director Rob Reiner and his wife Michele.

The couple’s son Nick, 32, has been charged with their murders, and the Daily Mail revealed last month that his siblings had made the difficult decision to cut off his legal fund.

Jake and Romy Reiner also decided not to attend Nick’s plea hearing this week, at which a public defender entered a not guilty plea on his behalf.

But, surprisingly, one family member did attend – and it’s a move that has appeared to signal the first crack in that united front.

Annie Reiner – Rob’s younger sister – was spotted at her nephew’s arraignment in downtown Los Angeles on Monday.

Before members of the press and the public were permitted inside, Annie was allowed into the courtroom and took a seat in the front rows.

The 75-year-old was seen smiling and waving at Nick as he was led in wearing brown jail garb and mouthed ‘hi’ back.

He remained largely silent for the rest of the three-minute hearing.

While Reiner’s siblings appear to have turned their backs on their brother, Annie is clearly standing by her nephew.

A source close to the family claimed: ‘You could say it’s a feud and it’s really the three other kids deciding that they aren’t going to be supporting the person who [allegedly] killed their parents.

‘They have made it black and white – you’re either on that side or you’re on Nick’s side. If you’re on Nick’s side, they don’t want anything to do with you.

‘Annie has been clear that she’s supporting Nick and that’s offensive to the others.’

Other sources told the Daily Mail that any suggestions of a family feud are false.

The Daily Mail understands that Annie had grown somewhat distant from Rob’s family in the years before his death.

And yet, in the aftermath of the December 14 killings – when Rob and Michele were found stabbed to death in their Brentwood home – relatives gathered at Annie’s LA property, as the family reeled from the shock. 

One source said Annie’s work as a psychoanalyst – a type of therapist – may have compelled her to have sympathy for Nick. 

This week, Annie and a male companion left the courthouse just minutes before LA County District Attorney Nathan Hochman confirmed that prosecutors are still weighing whether to seek the death penalty.

Monday’s hearing marked the first time a judge allowed Nick to be photographed in custody.

His uneven buzz cut and receding hairline accentuated his resemblance to his famous father – a chilling visual reminder of what prosecutors allege is a case of patricide.

Nick – who had been battling mental health problems and drug addiction – was arrested within hours of the killings in the Downtown LA area near USC and formally charged with his parents’ murders.

At Monday’s hearing, he conferred with his attorney, public defender Kimberly Green, who entered a not guilty plea on his behalf. He remains in LA County jail on a no-bail hold.

His siblings have maintained they will not provide any financial assistance to their brother. High-powered defense attorney Alan Jackson withdrew from the case in January, paving the way for the Public Defender’s Office to take over.

TMZ executive producer Harvey Levin told Fox & Friends last week that Reiner is ‘almost childlike in jail.’

‘He can’t process the consequences of what he’s done. He knows what he did. He just can’t understand where he is right now, and I know that sounds crazy, but he is out of his head right now,’ Levin added.

A close family friend said Annie’s decision to show up in court could deepen already simmering tensions.

‘The shock [among the children] has worn off, the grief is still there, and now it’s been replaced with rage. They are beyond angry, and that will extend to any extended relatives who decide to support Nick,’ the friend said.

Nick is due back in court on April 29, when the case will move into its next procedural phase.

At that appearance, the court is expected to address scheduling for the preliminary hearing – where prosecutors will lay out the evidence they believe is sufficient to send the case to trial.

It is also possible that discussions surrounding capital charges will begin to crystallize.

The Daily Mail has contacted the Reiner family for comment.