When Nick Reiner was photographed alongside his family at the Los Angeles premiere of his father’s comedy musical, “Spinal Tap II,” in September, he wasn’t smiling. Instead, the son of legendary Hollywood director Rob Reiner and producer Michele Singer Reiner stood impassively for the family portrait alongside his siblings.

Rob and Michele Reiner's cause of death has been formally revealed after their son, Nick Reiner, made his first court appearance in the double murder case.

Now, the expert has reported Hollywood director Rob's death was caused by "multiple sharp force injuries".