There was a significant conversion from coroners' offices to medical examiners systems between 1960 and 1989, but Hanzlick, who has tracked the numbers, says the trend has since stalled. No states have converted to a medical examiner system since 1996, and only six counties have converted since 2000. One county even reverted to a sheriff-coroner system, in which the sheriff also serves as the coroner. This situation, Hanzlick said, raises questions of independence because the agencies have different goals.
"The medical examiner or coroner should remain free of law enforcement influence and control," he said.
Experts also say that investigators who are not trained in forensic pathology can spell big problems for death investigation, creating opportunities for infectious diseases to go undetected, innocent people to go to jail, and homicides to slip through the cracks by being ruled accidental.
Dr. Michael Baden, chief forensic pathologist for the New York State Police and an expert witness in many high-profile murder cases, says he's seen mistakes and misinterpretations happen time and time again. The result?
"Lots of people wind up in jail who shouldn't be in jail, people end up on the streets who shouldn't be on the streets, and people get executed," said Baden, who is the former chief medical examiner of New York City. "Mistakes get made and people pay the consequences."
The Innocence Project, a nonprofit that works to exonerate inmates believed to be wrongfully convicted, called earlier this year for Mississippi to revoke the medical license of Steven Hayne, a medical examiner whose autopsies were scrutinized after two Mississippi prisoners he testified against were exonerated 15 years later. The group said that although Haynes claimed to be "board-certified" in forensic pathology, he was not actually a board-certified forensic pathologist.
Hayne has defended his work as a medical examiner and says he is a victim of a witch hunt by the Innocence Project and other death penalty opponents.
The state announced earlier this month that it was terminating his contract, although it cited hiring a full-time medical examiner for a vacant position, not the complaints, as its impetus.
This, according to Baden, points to the number one problem in death investigation: a lack of training. Many of the people performing autopsies, he said, aren't properly trained or qualified. For example, most people who do autopsies in murder cases are certified in hospital pathology, dealing with natural diseases like cancer, but then end up conducting autopsies in violent, suspicious and unexplained deaths.
"It's a significant problem," Baden said, adding that although there are excellent coroners in the country, "The work in medical examiners offices in which they have forensic pathologists tends to be very superior to coroners offices in general."
He said some kind of federal mechanism or support is needed to train more forensic pathologists – there are only about 400 in the country at present – or to appoint a federal official charged with improving death investigation.
"Forensic pathologists are really the frontline of terrorism acts and bioterrorism acts," said Baden. "If someone dies of a new bacterium or virus or anthrax or smallpox, the medical examiner will be the first to do the investigation. We have to train people to recognize deaths that may involve chemicals or biological agents."