From the moment the police found Michelle O'Connell, a young, single mother, dying from a gunshot to the head, there were troubling questions about what happened inside the house in St. Augustine, Florida. The fatal shot came from the service weapon of her boyfriend, a local sheriff's deputy. O'Connell had just broken up with him and was packing to move out of his house. And barely an hour before she died, O'Connell had texted her sister to say she would soon be there to pick up her four-year-old daughter. Yet, none of this troubled detectives from the St. John's County Sheriff's - all fellow officers of O'Connell's boyfriend. Within hours, they concluded that O'Connell had committed suicide. Those critical questions remained unanswered for nearly two years, until Walt Bogdanich, an investigative reporter for The New York Times, began examining the death of Michelle O'Connell - a case that had deeply divided law enforcement agencies in Florida and raised broader issues of how the police investigate one of their own, particularly in instances of domestic violence. Bogdanich found that the criminal justice system had failed almost from the moment the fatal shot was fired. Evidence wasn't collected. Neighbors weren't canvassed. Important interviews were not conducted. Medical examiners concocted absurd theories to support the suicide conclusion and prosecutors blindly endorsed them. The Times's investigation, conducted in conjunction with the PBS investigative program Frontline, was part of a broader examination of how the police deal with the corrosive and persistent problem of domestic violence in their ranks.