At the age of 16, Rob Reiner came up with this joke. He passed it along to his father, the pioneering director and comedian Carl Reiner, who passed it to Mel Brooks. Soon, the joke found its way into the duo’s seminal double act,

Nick Reiner briefly appeared in court in the killing of his parents, Rob Reiner and Michele Singer Reiner, who'd suffered "sharp force injuries."

Rob Reiner's son Nick Reiner was "entitled" and "wanted to live a life that didn't exist," a source close to the family tells PEOPLE. The 32-year-old, now charged with killing his parents, previously spoke about having "no identity" and "no passions" growing up in the shadow of a famous father.

Rob Reiner and Michele Singer Reiner's two other children have spoken out for the first time as their brother, Nick Reiner, appeared in court to face charges for the murders of his parents. Jake and Romy Reiner released the following statement on Wednesday:"Words cannot even begin to describe the unimaginable pain we are experiencing every moment of the day.

In the wake of their tragic killings, the Hollywood couple are survived by Nick and their two children, Jake, 34 and Romy, 28. Rob was also father to daughter Tracy, 61, from his first marriage to the late Penny Marshall.

After finding the slain couple, investigators focused on their younger son, Nick, as a suspect. He was formally charged with murder on Tuesday.

Reiner and his wife, Michele Singer Reiner, were found dead inside their Brentwood, Calif. home on Sunday afternoon at 78 and 68, respectively. The Los Angeles Police Department said at the time that their deaths were being investigated as a homicide, but that they had not identified a suspect and no one had been detained.

Rob Reiner and Michele Singer Reiner's children, Jake and Romy Reiner, remembered their parents in their first statement since the couple's deaths: 'Words cannot even begin to describe the unimaginable pain.

Nick Reiner, who didn't enter a plea Wednesday, faces murder charges after, authorities say, he killed his parents at their Los Angeles home over the weekend.

Billy Crystal, Larry David, Martin Short, and more stars shared a heartfelt tribute for Rob and Michelle Reiner, who were killed in a fatal stabbing.