“Mom, open up, I’m cold”: The 3:07 a.m. call from a son who died 2 years ago that uncovered the worst family betrayal.

to flicker violently. The state-of-the-art sound system, meant to play soft instrumental music, erupted into a loud, piercing static that made everyone cover their ears in discomfort. Then, instead of music, a crystal-clear recording echoed through every speaker across the garden.

“We have to make sure the escape valve is completely broken before he continue reading …