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How Can a Healthcare Serial Killer Be Spotted and Stopped?

A fact-based movie about Charles Cullen blames the system.

Key points

  • "The Good Nurse" shows how a killer exploited a hospital system that was willing to overlook suspicious behavior.
  • Mystifying Cullen’s motives in this story eased his degree of culpability.
  • Red-flag behaviors that reveal these predators can help to document and catch them.
Drawn by K. Ramsland
Charles Cullen
Source: Drawn by K. Ramsland

As we’re watching the trial in England of neonatal nurse Lucy Letby for the murder of seven babies, Netflix has aired a fact-based movie, "The Good Nurse," based on Charles Graeber’s book by the same name. Nurse Charles Cullen’s murders of at least 29 patients, with far more suspected, cast a harsh light on enabling procedures in the healthcare system where he worked. For a decade, he operated at 16 healthcare facilities, often under a cloud of suspicion, without being stopped. When the pressure was on, he merely moved on.

Cullen is one of the serial killers on whom I focused in Inside the Minds of Healthcare Serial Killers, because he showed many of the red-flag behaviors I list based on studies of dozens of cases. Due to the shared commonalities in method and motive, these offenders comprise a subgroup of serial killer who can be prospectively profiled (i.e., evaluated for risk of future danger).

On the evening shift of June 15, 2003, at Somerset Medical Center (SMC) in Somerville, New Jersey, someone used the computer system to order the heart medication, digoxin. It was canceled, but the drug went missing. A cancer patient went into cardiac arrest from unauthorized digoxin. Two weeks later, digoxin killed another patient. SMC’s administrators sent reports and samples to the New Jersey Poison Control Center and launched an internal investigation. Forty-three-year-old nurse Charles Cullen had ordered digoxin for patients under his own care, but state laws prevented SMC from learning if Cullen had caused trouble at other facilities.

Toxicologist Steven Marcus, director of the New Jersey Poison Control Center, warned SMC about a poisoner on their staff. Hospital officials thought he’d rushed to judgment. Yet the facility found that Cullen was the common factor in four suspicious cases. When several more “unexplained fatal incidents” occurred between July and October, Cullen was fired for misrepresenting information on his employment application.

Somerset County Prosecutor Wayne Forrest had already launched an investigation. The detectives assigned to the case, Timothy Braun and Daniel Baldwin, looked at records from nine institutions and, despite roadblocks, identified an incriminating pattern. They arrested Cullen.

During the movie’s final scenes, Cullen shows some bizarre behavior as he resists confessing. Yet, he did finally admit to the four cases and added many more. Over the past 16 years in 10 healthcare facilities, Cullen had overdosed up to 40 patients, with the intent to kill. It was easy, he said, to go from one facility to the next and to experiment with different substances. He blamed administrators for letting him get away with it.

Motivation to Kill

Although he’d initially claimed that he’d killed patients to end their suffering, as the cases were opened, it was clear that many of his victims had not been suffering. Some had been recovering. In addition, Cullen had committed malicious mischief. He’d thrown out expensive drugs and put insulin into IV bags stored in a closet to see what would happen. He was no mercy killer. In fact, despite the movie claiming he never said why, it’s not difficult to see how his episodes of depression and failure (debt, divorce, rejection, another arrest) often triggered his aggression: He victimized patients to empower himself. Killing made him feel better.

“It was never about anyone but Charlie Cullen,” Graeber said on the news program, "60 Minutes." “He did what he did because of his own needs, his own compulsions.”

In a passive-aggressive manner, Cullen wrapped his blame in a narrative of advice for hospitals about how to make it more difficult for people like him: There should be protocols for accountability for staff and for drug-handling procedures. Among them would be installing surveillance cameras, the use of swipe cards and bar codes, and a daily count of lethal medications. There should be a national database for updating the employment history of healthcare workers. Institutions should pass information along to one another, and hospitals should pay attention to the mental health of their employees. Poor performance such as his should be reported to the state board of nursing.

Laws at the time prohibited warning future employers based only on suspicion, and it’s notoriously difficult to collect evidence for such killers. Healthcare providers know how to use subtle murder methods like smothering and overdoses, and they have access to drugs that can poison patients undetected. Unless some specific behavior inspires suspicion, they might effectively hide their crimes. SMC administrators said they did not know that Cullen had been investigated elsewhere. When they’d checked his credentials, they’d learned nothing that would have prevented them from hiring him.

Red Flags

This spotlights the importance of behavioral patterns. There are red flags. While none of these items is itself sufficient to raise suspicion, a number of them in constellation should be alarming to colleagues and facility administrators:

  • Statistically, there is a higher death rate when the suspected person is on shift.
  • The patient deaths were unexpected.
  • The death symptoms were not expected.
  • The suspect has moved around from one facility to another.
  • The suspect is associated with missing medications.
  • Patients have complained about the person’s treatment of them.
  • The suspect is seen with patients who soon died, including patients not in their care.
  • The suspect is secretive or has a difficult time with personal relationships.
  • The suspect has a history of mental instability or periodic depression.

Beatrice Crofts Yorker, an expert on these cases, adds that healthcare professionals who preyed on their patients were often caught in other types of lies or deceptive behavior, such as hiding a past criminal record or lying about previous employment. “They were liars more often than they were criminals,” she said. This includes even an innocuous lie like the wrong date of employment or a number on their license plate.

In response to Cullen’s case, officials in Pennsylvania and New Jersey developed new policies and procedures. State regulators strengthened nursing standards, with new rules and harsher penalties. They also introduced the Safe Health Care Reporting Act, which would expand the current National Practitioner Data Bank to include all licensed healthcare workers, not just physicians. Legislation was considered to protect hospitals from lawsuits should they have solid reasons to offer a negative evaluation of a former employee.

Cullen’s acts are no mystery, and better awareness of how someone like him operates will equip hospitals with the tools they need for improved documentation. His advice, while grating, should be taken seriously.


Assad, M. (2005, May 21). Cullen Gives Tips for Stopping Killings. The Morning Call.

Graeber, C. (2013). The Good Nurse: A True Story of Medicine, Madness, and Murder. New York, Twelve.

Crofts-Yorker, B., et al. (2006). Serial murder by healthcare professionals. Journal of Forensic Sciences. 51 (6). 1362–1371.

Ramsland, K. (2007). Inside the minds of healthcare serial killers: Why they kill. Westport, CT: Praeger.

Ramsland, K. & DeVito, D. (2011). Nurses Who Kill in Nursing Malpractice, 3rd Ed. Tucson, AZ: Lawyers and Judges Press, 909-923.

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