At 17, I was just babysitting for extra cash. The Mercer twins were asleep upstairs when their parents, Willa and Dorian, left their usual note: “Back by midnight. Help yourself to food.” But midnight came and went. By 4 a.m., I turned on the TV—and froze. Their faces were on the news. “BREAKING: Local Couple Arrested in Multi-Million Dollar Fraud...