There was blood in Nick Reiner’s Southern California hotel room the night his parents were killed, according to TMZ. Nick Reiner checked into a Santa Monica hotel Sunday morning, where authorities reportedly said he “left a trail of blood” after arriving around 4 a.m. Hotel staffers later foun d the room’s shower “full of blood.” Filmmaker Rob Reiner, 78, and his producer wife Michelle Reiner, 68, were found dead with stab wounds in their Los Angeles home Sunday afternoon. Their 32-year-old son was arrested on suspicion of murder Monday. The case is expected to be handed to prosecutors on Tuesday. Eyewitnesses said Nick, who has a history of substance abuse, appeared “tweaked out” Saturday when he arrived at the hotel. He and his father had earlier been involved in an apparent verbal confrontation at a party hosted by comedian Conan O’Brien, according to TMZ. That hasn’t been confirmed by police. TMZ reported that Nick never formally checked out of the hotel, and was tracked down by authorities roughly 20 miles away near downtown Los Angeles. With News Wire Services ...read more read less