In TV crime dramas and detective novels, every suspicious death is investigated by a highly trained medical professional, equipped with sophisticated 21st century technology.

The reality in America's morgues is quite different. ProPublica, in collaboration with PBS "Frontline" and NPR, took an in-depth look at the nation's 2,300 coroner and medical examiner offices and found a deeply dysfunctional system that quite literally buries its mistakes. We discovered cases in which blunders by doctors have put innocent people in prison cells, allowed the guilty to go free and left some cases so muddled that prosecutors could do nothing.

We surveyed almost 70 of the largest coroner and medical examiner systems in the country and learned that more than one in five physicians working in the country's busiest morgues are not board certified in forensic pathology, the branch of medicine focused on the mechanics of death. Experts say such certification ensures that doctors who do autopsies have at least basic skills.

The National Academy of Sciences has raised questions about the professionalism of the country's death investigation system, releasing a 2009 report describing the shortcomings of coroner and medical examiner offices, from inadequate resources to poor scientific training to substandard facilities and technology. The academy called for the creation of uniform federal standards for death investigation, recommending that certification in forensic pathology be mandatory for doctors. Their report also recommended replacing elected coroners with medical examiners.

ProPublica, with our partners, also took a close look at the special challenges posed by unexpected deaths of babies and toddlers. Our reporting showed that medical examiner and coroner offices have repeatedly mishandled those cases, helping put innocent people behind bars. We analyzed nearly two dozen cases in the U.S. and Canada in which people have been accused of killing children based on flawed or biased work by forensic pathologists, and then later cleared.