The heartbreaking murders of Rob Reiner and Michele Singer Reiner are the focus of a new episode of TMZ Investigates, which aired Friday (Jan. 9) on Fox.
The special dives into unsettling new details about the case — including the state of the investigation, a key missing piece of evidence, and the mental health struggles of their son, Nick Reiner.
The 32-year-old faces two counts of first-degree murder for the stabbing death of his parents in December 2025.
Nick Reiner’s Troubled Rehab History
The documentary revisits Nick Reiner’s years-long battle with addiction, which reportedly led to 18 rehab stints. Many were only 30-day stays — long enough to detox, but too short to address deeper mental health concerns.
READ MORE: Rob + Michele Reiner’s Final Hours: From Party Argument to Family Tragedy
“His first rehab stint was when his parents found him doing both Percocet and Xanax with a friend,” TMZ producer Olivia Heinle said in the documentary.
Dr. Drew Pinsky, an addiction expert not connected to the case, added: “Thirty days for me seems almost meaningless for someone with Nick’s history. What you want is something structured and long-term. Parents have a hard time accepting that.”
Nick also allegedly picked up dangerous habits during treatment. TMZ executive producer Charles Latibeaudiere noted that one fellow patient told him heroin was easier to score than prescription pills.
The Murder Weapon Still Hasn’t Been Found
One of the most shocking revelations in the episode: the knife allegedly used in the killings still hasn’t been recovered.
Kevin Winter, Getty Images
“This is a critical piece of evidence,” Harvey Levin explained. “If Nick bought the knife before the murders, that suggests premeditation. If it came from the kitchen, it could suggest spontaneity. But right now, that weapon hasn’t been found.”
The absence of the knife could complicate the prosecution’s ability to prove intent.
A Mental Health Diagnosis + Past Outbursts
According to TMZ, Nick was diagnosed with schizoaffective disorder in 2020 — a serious mental illness that combines features of schizophrenia with mood disorders like depression or mania.
READ MORE: Who Is Nick Reiner? Inside the Troubled Life of Rob Reiner’s Son After Parents’ Deaths
Before his diagnosis, sources say Nick was also using meth, which can severely worsen symptoms. At one point, TMZ reports, he had a violent outburst that involved “tearing up” his parents’ home.
Where the Case Stands Now
Nick Reiner was arrested on Dec. 14, 2025 — hours after Rob and Michele were found stabbed to death in their Los Angeles home.
He now faces:
- Two counts of first-degree murder
- A special circumstance for multiple murders
- An enhancement for using a deadly weapon
As of Jan. 7, Nick’s attorney, Alan Jackson, officially withdrew from the case, citing “circumstances outside of our control.”
READ MORE: What Is Parricide? Inside One of the Rarest + Most Shocking Crimes
However, before stepping away, he told reporters, “Nick Reiner is not guilty of murder. Print that.”
A Family with Hollywood Legacy
Rob Reiner — beloved director of Stand by Me, The Princess Bride, and When Harry Met Sally… — met Michele Singer in the late ’80s.
They raised three children together: Jake, Romy, and Nick. Rob also adopted daughter, Tracey, from his first marriage to actress/director Penny Marshall.
Michael Loccisano, Getty Images
Their deaths stunned Hollywood — and the case continues to unfold.
Celebrities Who Were Murdered
It’s shocking to hear when one of your fave actors, musicians or models is murdered. In fact, many of them still haunt us to this day. Below, discover 25 who were killed.
Gallery Credit: Natasha Reda
