Hollywood and fans are reeling over the killing of Rob Reiner and his wife Michele … and the family is speechless, finding it difficult to comprehend the news.

TMZ broke the story … the legendary actor-director and his wife were slain in their Brentwood home Sunday … and we’ve learned the couple’s son Nick was in law enforcement custody as of Monday morning, being questioned about their deaths.

Tracy Reiner — Rob’s adopted daughter from his marriage to ex-wife Penny Marshall — told NBC News she had just seen her father the day before for a family gathering.

The actress — best known for her role in “A League of Their Own” — told the outlet … “I came from the greatest family ever. I don’t know what to say. I’m in shock.”

TMZ broke the story … Rob and Michele suffered lacerations consistent with knife wounds, and LAPD’s Robbery Homicide Division is investigating the case.

Billy Crystal and Larry David showed up Sunday night at the house of their longtime friend Rob Reiner, who was stabbed to death with his wife Michele, allegedly by a family member.

TMZ obtained photos of Billy arriving at the Brentwood home of Rob and Michele after the couple’s throats were slit by a family member, possibly after a heated argument, according to sources with direct knowledge of the case. PEOPLE reported their son, Nick, is being questioned by police. LAPD’s elite Robbery Homicide Division is investigating the double homicide.

As you can see, Billy and his wife, Janice, appear sad and emotional, with Janice wiping tears from her eyes as the two left the area around where police roped off the crime scene. One neighbor told ABC7 that Billy looked as if he was about to cry.

Rob Reiner spent some of his final hours in conversation with actor and comedian Eric Idle … speaking with him for more than an hour before Reiner and his wife, Michele, were tragically killed at their Los Angeles home.

The “Monty Python” star took to X on Sunday night … writing, “Rob Reiner was a lovely man. I spoke to him last night for over an hour. I always enjoyed his company. I met him at his Dad’s in 1975. He was telling me about filming at Stonehenge and his thoughts for the future.”

He went on to say … “This is so awful. I shall miss him. A clever, talented, and very thoughtful man. So awful.”

Reiner and Idle were friends for 50 years.

TMZ broke the story … Rob and his wife Michele Singer Reiner were killed Sunday — suffering lacerations consistent with a knife.

We’re told a family member murdered the two, possibly after an argument, though it’s unclear what exactly triggered the violence. PEOPLE reports the couple’s son, Nick, is being questioned in connection with the murders.