Nick Reiner was a "ticking time bomb" prior to fatally stabbing his parents. In the wake of Rob Reiner and Michele Singer Reiner's son being arrested and charged with their murders on Sunday, we're hearing more about just how volatile the 32-year-old could get. On Monday, a source told the DailyMail.com the When Harry Met Sally director and his wife allowed their son to live in their guesthouse, but were getting to a point where they wanted him out: "Nick had been living in their guesthouse, the same one he destroyed more than once, but it had been like a revolving door all his adult life.