Health professionals who kill multiple patients share common profile, expert says

As unthinkable as the alleged crimes of Elizabeth Wettlaufer may be, the Woodstock, Ontario nurse is not alone as a health care professional accused of murdering multiple patients.

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Criminal history includes several high-profile cases of so-called health-care killers — doctors, nurses and other health care workers who were able to commit murder over an extended period of time thanks to their professional power and their patients' vulnerability.

American nurse Donald Harvey is believed to have murdered up to 57 hospital patients over 17 years in the 1970s and 80s. He's currently serving multiple life sentences.

According to Western University criminology professor Michael Arntfield, Harvey's crimes led to more research and a greater understanding of murders committed by health-care professionals. As similar cases emerged, so did a profile for this type of offender.

Mother Teresa Syndrome

"Health-care killers tend to make a very specific type of offender, with a very specific type of M.O., and fortunately they're rare," Arntfield said in an interview with CBC News.

Since 1970 there have been 41 cases of documented health-care killers in the United States, according to Arntfield's research. To his knowledge, there have been none in Canada.

In many cases, Arntfield says the offenders share a common psychological disorder that criminologists refer to as the "Mother Teresa Syndrome."

"They tend to see themselves or hold delusions that they are acting in some divine capacity. They often begin operating under the delusion that they are helping these people, that they are ending their suffering."

One of the most notorious examples is Charles Cullen, another American nurse who confessed to killing 40 patients at hospitals in New Jersey and Pennsylvania during his 16 year career. Experts believe it's possible that Cullen actually killed as many 400 patients. Using fatal doses of drugs, Cullen believed he was ending his patients' suffering.

However, Arntfield says the mercy-killing motivation that may drive a health-care killer changes as the murders continue. "Like many serialized offences it begins to take on a more compulsive dimension and is really more about ego satisfaction."

Whereas most conventional serial killers are predominantly male, Arntfield says about half of health-care killers are female.

Catching health-care killers

Authorities began to investigate Donald Harvey after the doctor performing an autopsy on one of his victims found traces of cyanide. Charles Cullen's crimes were uncovered when co-workers began to notice strange behaviour and missing drugs.

Arntfield says since the crimes of health-care killers often go unnoticed for years.

Jane Meadus, a staff lawyer and institutional advocate at the Advocacy Centre for the Elderly, says that's often because death is a common occurrence in health-care facilities and isn't normally seen as suspicious.

"You have to remember: people in long-term care die, they are not unexpected. One more on top of that just doesn't seem so unusual," Meadus told Metro Morning host Matt Galloway on Wednesday.

That's partly why the criminal cases against health-care killers usually lack eyewitnesses or physical proof and are built on a "preponderance of circumstantial evidence," Arntfield said.

However, he says, in some cases bodies of victims will be exhumed and examined.

While suspicious behaviour or an autopsy may lead to charges, Arntfield says the short amount of time between the beginning of the police investigation into Elizabeth Wettlaufer, the identification of eight victims, and her arrest suggests an admission was made at some point.

CBC News has learned that the investigation into Wettlaufer began in September after staff at Toronto's Centre for Addiction and Mental Health (CAMH) provided police with information the former nurse provided about the deaths of patients.