Rob Reiner's close friends, including Billy Crystal and Albert Brooks, are showing up to be "fiercely" protective of the late director's kids Romy and Jake in the wake of the murders, a source tells PEOPLE.

Both the Hollywood community and moviegoers in general are still reeling from the shocking deaths of Rob Reiner and his wife Michele. The pair were killed in an apparent homicide, shortly after Rob and his son Nick Reiner (the prime suspect) argued at a party.

The “Stand by Me” filmmaker and his wife of 36 years, Michele Singer Reiner, shared three children: Jake, 34, Nick, 32, and Romy, 28. Rob also had another daughter, Tracy, 61, whom he adopted during his first marriage to Penny Marshall.