It started with a 911 call at 8:49 a.m. on Saturday, Dec. 17, 2011. Justin DiPietro told a Waterville dispatcher that his 20-month-old daughter, Ayla Reynolds, was missing. Three years, 20 searches and thousands of tips later, Ayla has yet to be found. Her mother, father and police, and those associated with them, have been at the epicenter of the biggest and most expensive criminal case in the state’s history.These are their stories.