INDIANAPOLIS — Amani Day was a healthy 2-year-old, running and playing and laughing like any other child before being found still and cold in a bed next to his grandmother one October morning. Amani's sudden death immediately sparked suspicion within Indy police's child abuse unit. In the home, a distraught grandmother told police about how she tried to revive the boy when she found him unresponsive in the morning. But investigators learned th…