Article continues below advertisementNick Reiner, the son of Rob Reiner and Michele Singer Reiner, has become a key focus of the ongoing investigation into his parents' apparent homicide.OK! learned Rob and his wife were found dead in their Brentwood home on December 14 after suffering "lacerations consistent with a knife." Police did not identify the individuals, but the Reiner family later issued a statement confirming the couple's deaths."It is with profound sorrow that we announce the tragic passing of Michele and Rob Reiner," a spokesperson said.