The Saint Barnabas Insulin-Poisoning Investigation and Charles Cullen’s Dismissal began with patients suffering unexplained insulin crises and ended without an official conclusion. Hospital investigators found evidence that insulin had been deliberately introduced into intravenous bags, identified Charles Cullen as a compelling suspect, and tried to involve the police. Yet they could not connect the suspected poisoning episodes to Cullen or prove what had happened to individual patients. The investigation closed in late December 1991; Cullen was fired in the first week of January 1992, and the insulin spikes stopped.

The poisoning signal

The inquiry gathered force when a bag connected to patient Fred Belf tested positive for insulin. Belf had received heparin and, by midday, was vomiting and unable to keep down orange juice. Doctors ordered intravenous dextrose alongside the heparin. After the connection was made between the heparin bags and patients’ symptoms, nurses disconnected Belf’s heparin; he soon began to improve. Staff sealed his IV bag in sterile plastic and sent it for testing.

The test result was not the only warning. Microscopic examination found tiny needle punctures on the bag, including three along its edges. Bags could be pierced accidentally while being connected to a stopcock, but not ordinarily around their perimeter. Investigators had two bags as physical evidence and reports of similar episodes involving Belf and Anna Byers. They searched critical-care records for other unexplained insulin crashes and found that patients had been collapsing repeatedly for months. The episodes crossed intensive-care, critical-care, and cardiac units, with codes sometimes overlapping so that nurses had to leave one emergency to attend another.

Laboratory results sharpened the concern: affected patients had exceptionally high, unprecedented insulin levels, much of it identified as foreign to their bodies. Investigators first considered ordinary medication errors, such as a nurse misreading an order or a vial being mislabeled. But the charts showed neither a doctor’s insulin prescription nor a nurse’s notation that insulin had been administered. That left two troubling possibilities: a drug had been given without an order and then omitted from the record, or the administration had not been accidental.

From hospital inquiry to police refusal

Thomas Arnold brought his findings to Joe Barry, Saint Barnabas’s senior vice president in charge of security. Barry had previously served for thirty years as a police officer, including as a major with the New Jersey State Police. Arnold and Barry ruled out patients’ visitors as likely suspects, then compared nurses’ work schedules with the times of the patient codes. Only three nurses had been working every code; Cullen drew their particular attention.

Cullen’s manner during the inquiry added to investigators’ concern but did not constitute proof. Other staff members seemed nervous about their jobs, reputations, and the patients involved. Cullen appeared unconcerned and defiant. Because he worked through a staffing service rather than as a direct hospital employee, his shifts were irregular and difficult to schedule around. When investigators eventually brought him into a conference room, he refused to answer questions. His employment arrangement also complicated the paper trail: a later account explained that a staffing company had hired him partway through his Saint Barnabas tenure, so the hospital file covered only its final two years.

Arnold and Barry believed they had grounds to ask police for help. On March 5, 1991, they presented the case to Livingston’s chief of police over lunch at an Italian restaurant. They had suspected homicides, physical evidence of drug tampering, and a suspect among the hospital staff. The chief declined to pursue the matter, saying he did not think the evidence was sufficient and that the hospital should handle it internally. The investigators could not know whether he was trying to spare the hospital a difficult case or believed the evidence could not support a police investigation. Either way, the responsibility remained with Saint Barnabas.

Surveillance, controls, and unresolved cases

Arnold and Barry tried to catch whoever was tampering with the bags. For several weeks they used stop-motion cameras in the medication-storage room, interviewed physicians, staff, and patient families, and introduced a drug sign-out protocol that subjected insulin to stricter control, like drugs such as morphine. The measures were intended to make access and handling more visible, but they did not produce proof tying Cullen to a particular bag or patient.

The investigation’s central weakness was the distance between a disturbing pattern and a provable case. Staff assembled timelines and mortality rates for Cullen’s period working across intensive-care, critical-care, and cardiac units. The deeper they searched, the more questionable cases they found, but the patients had complicated illnesses and symptoms. Investigators could not directly connect unexplained insulin spikes to a single incident, to Cullen, or, in some cases, to a patient’s eventual death. Cullen’s work as a floater, including unscheduled shifts, made comparisons between his presence and events on the units harder still. The pattern justified alarm, but it did not resolve individual causation.

In October, two more Saint Barnabas patients in the cardiac-care unit suffered unexplained hypoglycemia and were found connected to insulin-tainted IV bags. Investigators had more reason for suspicion, but still no evidence they could prove against Cullen. Then Cullen left the hospital. The insulin-spike problems disappeared with him, a sequence that was striking but did not, by itself, settle the question of responsibility.

Staff unease and the later record

The tightened insulin procedure also exposed how little the staff had been told. Amy Loughren’s manager described an insulin adjustment form that required nurses to estimate how much insulin remained in a vial and enter an electronic signature. Loughren considered the estimate unreliable and refused to sign. She asked why insulin was being treated like a narcotic and what made it dangerous; her supervisor did not explain what had happened. The new procedure was evidence of heightened control, but the silence around its reason left nurses to infer that patients on their unit might have been harmed.

The investigation’s uncertainty later became personal for Loughren. When a detective showed her a Pyxis record from the night Reverend Florian Gall died, she recognized Cullen’s activity and could no longer dismiss the possibility that her friend had done something terrible. She was frightened of the risks of cooperating with investigators, including the possibility of losing her job, but later assisted them. Her recognition of the record belonged to a later investigation, not to proof produced by the Saint Barnabas inquiry; it nevertheless shows how the suspicion surrounding Cullen returned in a new setting.

Fragments of the Saint Barnabas investigation were recovered after Cullen’s arrest. Incident reports described conduct that resembled methods associated with his later crimes: he had repeatedly checked a patient’s insulin levels at inexplicable intervals, and on another occasion left an unlabeled IV hanging after his shift instead of the prescribed potassium chloride solution. When contacted at home, he was described as apathetic and said that if the bag was hanging there, it must contain the prescribed solution. The report did not establish what was in the bag or whether it was one of the saline IVs Cullen later admitted to randomly spiking with insulin. A further clarification made the episode more troubling: he had withheld prescribed medication, substituted an unlabeled bag, and clamped it so that the next nurse would start the drip. Yet the substance remained unknown, and the record did not convert suspicion into a demonstrated Saint Barnabas poisoning.

Closure and significance

The investigations closed in late December 1991 without reaching a conclusion. Cullen was fired during the first week of January 1992, and the insulin spikes stopped. Saint Barnabas later maintained that the two facts were unrelated and that its administration had lacked reason at the time to believe Cullen was a danger to patients. The account preserves both the force of the circumstantial pattern and the limits of what investigators established: unusual bags, repeated crises, and concerning conduct did not yield a proven link between Cullen and the affected patients.

The inquiry therefore stands as an early warning that remained unresolved rather than a completed criminal case. It shows how a cluster of clinical anomalies could prompt internal surveillance and new medication controls while still failing to overcome uncertain patient histories, scattered shifts, and the absence of direct evidence. The later recovery of fragments gave the old reports renewed significance, but it did not erase the distinction between warning signs recognized in retrospect and conclusions the original investigation could support.