Nick Reiner was acting strangely at Conan O'Brien's Christmas party, just hours before allegedly killing his parents. As we've been following, Rob and Michele Singer Reiner were heartbreakingly found dead on Sunday afternoon in their California home. Their 32-year-old son has been arrested for allegedly committing the killings. Previously, TMZ sources said Rob and Nick were caught getting into a "very loud argument" at the late-night star's holiday bash on Saturday night. Rob and Michele left shortly after.