Rob Reiner and wife Michele's cause of death confirmed as multiple sharp force injuries

The Los Angeles County Medical Examiner's Office has confirmed the cause of death for renowned director Rob Reiner and his wife, Michele.

The couple died at their California home in the early hours of Sunday (December 14) morning, with their son, Nick Reiner, having since been charged with two counts of first-degree murder in connection with the tragedy.

Authorities say that he was arrested a short distance away from the University of Southern California, hours after the discovery of his parents' bodies.

Reiner briefly appeared in court on Wednesday (December 17), shackled and wearing a blue anti-suicide smock, to face the charges against him.

When in court, Nick waived his right to enter into a plea. He was not visible to the cameras and spoke very little during his brief appearance. He simply said 'yes, your honour' when asked by Judge Theresa McGonigle if he understood he has the right to a speedy trial, BBC reports.

Nick Reiner stands accused of murdering his parents (Rommel Demano/Getty Images)

He is next due in court on January 7 next year.

The Los Angeles County Medical Examiner's Office determined that Rob and Michele's death was the result of multiple sharp force injuries, with the manner of death being ruled as a homicide.

The Los Angeles County District Attorney's Office had previously reported that Rob and Michele were stabbed to death.

As Reiner faced the court, his grieving siblings Jake and Romy shared their heartache over the loss of their parents for the first time.

Shared with People, Jake and Romy's heartbroken statement reads: "Words cannot even begin to describe the unimaginable pain we are experiencing every moment of the day.

"The horrific and devastating loss of our parents, Rob and Michele Reiner, is something that no one should ever experience. They weren't just our parents; they were our best friends.

"We are grateful for the outpouring of condolences, kindness, and support we have received not only from family and friends but people from all walks of life.

Rob and Michele were found dead in their home over the weekend (Amy Sussman/Getty Images)

"We now ask for respect and privacy, for speculation to be tempered with compassion and humanity, and for our parents to be remembered for the incredible lives they lived and the love they gave."

Rob Reiner was best known for directing classic movies like When Harry Met Sally, A Few Good Men, and The Princess Bride, as well as acting credits in The Wolf of Wall Street and, more recently, in New Girl and The Bear.

His wife of 36 years, Michele, who tied the knot with the movie maker in 1989, also enjoyed a career in the entertainment industry, initially starting as a photographer before dipping into acting, starring in the holiday movie Mixed Nuts.

She then went on to produce several of her husband's films, including Shock and Awe and Spinal Tap II: The End Continues, which was released this year.