in crime and punishment tonight, justice for a toddler. i want to show you her picture. this is cassie, it will be ten years next month since she died. i imagine it's a tough time of year for her family. cassie's mom left her with someone she trusted. while she was gone, cassie suffered a severe head injury. i can tell you as a doctor, but more importantly as a father of three young girls, this story really got to me. how cassie got those fatal head injuries remained a mystery for years. but to some in cassie's family, the facts didn't add up. turns out they were right. here's randi kaye. >> reporter: in the morning of january 18th, 2001, the only person at home with cassie was her mother's boyfriend, former marine, william veech. just before 10:00 a.m., veech called 911. by the time paramedics arrived, cassie, just 17 months, was unconscious.