Rob Reiner and his wife Michele Singer Reiner were discovered slain at their Brentwood home after Los Angeles Fire Department and Los Angeles Police Department crews responded to a medical-aid call and found severe throat lacerations consistent with stab wounds.Investigators said a loud argument involving the couple and their 32-year-old son Nick Reiner erupted during a large holiday gathering earlier, Romy Reiner found the bodies after a missed appointment prompted a welfare check, and search warrants and digital forensics are under way with no obvious signs of forced entry.Law enforcement booked Nick on suspicion of murder and initially set bail at $4,000,000 while the Los Angeles County District Attorney reviews forensic and digital evidence, later reports said he was being held without bail and placed on suicide watch, and sources told TMZ that Billy Crystal and his wife Janice Crystal rushed to the house and saw the slain bodies.