Article continues below advertisementThose close to the family "instantly knew" Nick Reiner killed his parents, famous Hollywood director Rob Reiner and wife Michele Singer Reiner. According to one longtime neighbor, the 32-year-old drug addict had a history of dangerous behavior before fatally slitting Rob and Michele's throats at their Los Angeles mansion on Sunday, December 14. "This is not the first time their son has been violent," the man, who wished to remain anonymous, told an outlet.