At first glance, there didn’t seem to be anything suspicious about Brady in the video. He looked like a devoted husband, standing by his critically ill wife’s side. His body trembled, and he appeared to be consumed by grief.

But Dave didn’t buy it. He didn’t think Brady was shaking from sorrow, he suspected it was excitement.

Something about Rachel’s death just didn’t feel right. In her final moments, her empty eyes shifted toward the camera, almost like she was looking straight at Dave in the surveillance room. There was a deep sadness in her eyes as if she were trying to send him a message.

Her medical records showed...