10 most prolific medical serial killers of all time

The Modus Operandi of serial killers can vary wildly. Some snatch their victims right off the street, others break into people’s houses. The weapon of choice might be a gun, knife, hammer or ligature. There may be a sexual element. There could be torture or mutilation involved.

One of the serial killer profiles that’s less discussed, less focused on, has an MO unlike the standard archetype. They don’t stalk the streets looking for victims, they don’t pounce, abduct, tie up, terrorise, slash, rape, or dismember. They are a very different breed indeed.

Who are the 10 most prolific serial killers ?

Many of the world’s most prolific serial killers are relative unknowns, despite racking up some truly horrifying kill counts | Image: Shutterstock

Historically, they’ve been known as ‘angels of mercy’. But it’s a moniker which affords far too much leniency and credit. They’re now called something far more apt… ‘Healthcare serial killers’ or ‘medical serial killers’.

We’re referring to the phenomenon of doctors, nurses and carers who exploit their positions of trust for their own nefarious and murderous ends. They target the vulnerable patients in their care, killing them for a variety of reasons: feelings of God-like power, financial benefit or just pure psychopathy.

Confirmed number of victims: 218

80% of the victims of the medical professional with the highest victim count in history were elderly women, although Dr. Shipman was also convicted of killing some people as young as 41. A few investigators even suspected the British Dr. Death of administering morphine in lethal doses to some children in his care. Shipman killed himself in his cell in 2004.

Dr Death: Unbelievable facts about Harold Shipman's crimes

Here are some of the most unbelievable facts about Harold Shipman's crimes

2. Miyuki Ishikawa

Confirmed number of victims: 103

This Japanese midwife worked with a few different accomplices during the 1940s, killing more than 100 new born babies. Often convincing poorer parents to pay to give their children up (the amount would, she’d say, be far less than the true cost of raising a child), she would then neglect, abuse and kill the infants. Ishikawa wasn’t the only person doing similar in Japan at the time and, incredibly, authorities were barely interested in the practice. She was found to have killed 103 babies, but the true number is likely to be much higher. Yet still Miyuki Ishikawa served just FOUR YEARS in prison.

Angels of death: The nurses who kill

We don’t like to think that the people that are put in place to care for us at our most vulnerable—the doctors, nurses and other medical professionals—are also the ones that could willingly commit murder

3. Niels Högel

Confirmed number of victims: 85

German nurse Högel was originally arrested after police discovered that he had intentionally administered lethal doses of heart medication to six patients in his care, killing them all. He had done it hundreds of times between 2000 and 2005. Sometimes he’d resuscitate them after they’d died to show off to colleagues. Mostly he wouldn’t. Högel was later found to have killed 85 people this way. His grim tally could be nearer 300.

4. Louay Omar Mohammed al-Taei

Confirmed number of victims: 43

While still beyond evil, there was at least an ideology at work behind Dr. Louay Omar Mohammed al-Taei's shocking medical murders. An Iraqi medical doctor working throughout the second Gulf War, he was often tasked with treating badly wounded policemen, soldiers and state officials. Instead of caring for them however, he would instead kill them. Louay would administer anticoagulants to any wounded pro-coalition patient, to make their bleeding worse and - in many cases - kill them. He did so because he had been recruited into an Iraqi Sunni insurgent group called Jamaat Ansar al-Sunna. He was arrested and tried in 2006 after killing 46 people.

Confirmed number of victims: 37

Ohio-born hospital orderly Donald Harvey claimed to have only killed out of ‘mercy’, racking up a shocking number of murders. Somehow he managed to kill between 37 and 57 mostly cardiac patients before being caught. Harvey used a variety of methods, substances and implements to 'euthanise' people without their permission, including: arsenic, cyanide, insulin, various poisons, morphine, the switching off of ventilators, suffocation and even the insertion of a coat hanger into patients' catheters (causing fatal peritonitis). He was serving 28 life sentences until his death in 2017.

Confirmed number of victims: 31

‘Jolly Jane’ spent six years in the late 19th century poisoning infirmed people in Boston, Massachusetts. Her ambition, she claimed, was ‘to have killed more people - helpless people - than any other man or woman who ever lived.’ Although she later confessed that her primary motivation was, in fact, sexual.

Confirmed number of victims: 29

Former US Naval officer Charles Cullen confessed to having killed up to 40 patients during his time as a nurse in his home state of New Jersey in the 1980s and 90s. Some criminologists estimate that Cullen may actually be responsible for more than 400 deaths. If true, it would make him the most prolific serial killer ever.

Charles Cullen: The killer nurse with an estimated 400 victims

Charles Cullen worked at numerous hospitals in the New Jersey area while his killing spree went largely unnoticed.

Confirmed number of victims: 29

Bavarian serial killer Letter would kill his victims with injections of various poisons, primarily large shots of muscle relaxants like suxamethonium and succinylcholine. In 2006 Letter was found guilty of 12 counts of murder, 15 counts of manslaughter and one of 'mercy killing'. He was sentenced to life in prison.

Confirmed number of victims: 27

In 1978, 18-year-old Swedish nurse Anders Hansson poisoned 27 elderly patients, by making them drink detergent. His Malmö Östra Hospital murder spree was only halted when one of his victims began screaming and loudly complaining of having a burning throat. Hansson has been incarcerated in a psychiatric care facility in Sweden for more than four decades now.

Confirmed number of victims: 26

French serial killer Marcel Petiot had no delusions of playing God or being an angel of mercy. He killed simply for money. During the Second World War, Petiot set up fake escape networks for Jews fleeing France. He was ‘inoculating them against disease’ before they left, he claimed. In reality he was injecting his victims with cyanide. When they died, he disposed of their bodies, but kept their possessions.

… Norweigien nursing home manager Arnfinn Nesset (22 victims, though there could be more than 140). Swiss retirement home nurse Roger Andermatt claimed only to kill ‘out of mercy’ (22+). Pediatric nurse Genene Jones would poison babies and then revive them, often failing in the latter (11+). French nursing assistant Ludivine Chambet was so traumatised by her sick mother’s death she dished out lethal drug cocktails to elderly patients (10). Nurse Petr Zelenka’s motivation was to ‘test out doctors’ when he poisoned patients (7+). Orville Lynn Majors killed elderly hospital patients who ‘annoyed’ her (6 confirmed, but thought to be many more) and British nurse Beverley Allitt, who overdosed patients with insulin (4).