“Julie has a very strict schedule she follows when it comes to cleaning various parts of the house. What I learned that day is that every three to four months she pulls all the furniture away from the walls in the spare bedrooms to vacuum behind them. Harper typically used one of the spare bedrooms when she came over… although we didn’t live together, she was there often enough that she had a few items in the closet and the bathroom.

“Anyway, Julie moved the dresser away from the wall and found an envelope containing a thumb drive on it. I suppose Julie was leery of Harper ever since she...