Frank Joseph Mazzacco Jr. was a 65-year-old Caucasian man who devoted much of his life to public education in New Jersey, teaching in Trenton’s public schools for roughly thirty-four years and at one time serving as president of the local teachers’ union. Away from the classroom he was rooted in central New Jersey, with records placing him in communities like Lambertville and the wider Hunterdon and Mercer County area, part of a family whose name surfaces in local census and genealogical listings. By the mid-1990s he was an experienced educator nearing the later chapters of his life, known in school records and union notes not as a transient figure but as someone who had spent decades inside the same system, advocating for colleagues and students alike.
In June 1996, Mazzacco was admitted to Hunterdon Medical Center in Flemington, a brick-front community hospital that served much of the surrounding county.
The details of his underlying illness were not made public, and at the time his presence there appeared unremarkable, one more older patient on a ward accustomed to serious cardiac and medical problems. On June 24, 1996, he died in the hospital; official records simply noted his passing on that date in Flemington, and he was later buried at Greenwood Cemetery in nearby Hamilton, in Mercer County. To his family and former colleagues, the death was initially understood as a hospital loss, not a crime scene, and there was no immediate suggestion that anything sinister had happened in his room.
What no one outside the institution realized at the time was that Mazzacco’s death fell in the middle of a troubling pattern at Hunterdon Medical Center. In 1996 the hospital had recently hired critical-care nurse Charles Cullen, who quietly moved between hospitals in New Jersey and Pennsylvania and would later be unmasked as one of the most prolific serial killers in American medical history. Cullen later acknowledged that during his tenure at Hunterdon he had murdered multiple patients by secretly adding powerful drugs, especially the heart medication digoxin, to their IV bags, causing sudden and often unexplained cardiac crises. Lists compiled by law-enforcement–linked reporting and by later reconstructions of Cullen’s victim timeline place Mazzacco among a tight cluster of patients who died on Cullen’s watch at Hunterdon that year, alongside names like LeRoy Sinn, Earl Young, Catherine Dext and Jesse Eichlin. Only years after the funeral did investigators and journalists begin to treat his June 24 death not as a natural passing, but as one more entry in the nurse’s hidden series of poisonings.
The unraveling of the case did not begin at Hunterdon but at another institution in New Jersey. By the early 2000s Cullen was working nights at Somerset Medical Center in Somerville, where a series of unexpected patient deaths finally drew the attention of hospital administrators and then law enforcement. Patterns in drug withdrawals and medical records led detectives Tim Braun and Danny Baldwin to suspect that a staff member was deliberately overdosing patients; they turned to Cullen’s colleague, nurse Amy Loughren, for help interpreting cryptic medication logs and computer data. Loughren eventually agreed to cooperate, wearing a wire to confront Cullen and helping police gather enough evidence to move in. In December 2003, Cullen was arrested and charged in connection with deaths at Somerset, and in subsequent interrogations he began to confess to a long trail of murders that stretched back across multiple hospitals and many years.
Once Cullen began cooperating, investigators revisited older deaths at the institutions where he had worked, including Hunterdon Medical Center. Hospital employment records, drug-dispensing logs and the tight clustering of sudden fatalities in 1996 allowed authorities to link several of those deaths to his admitted practice of surreptitiously poisoning patients under his care. Public victim lists released in the mid-2000s and widely reprinted in national outlets include Mazzacco among the twenty-two New Jersey patients whose killings Cullen acknowledged and for whom he was ultimately sentenced, describing him as a longtime Trenton public-school teacher and former union president who died at Hunterdon Medical Center on June 24, 1996. With those pleas on the record, his death came to be counted among Cullen’s confirmed homicides rather than an unresolved hospital loss.
In 2006, after a series of court appearances in New Jersey and Pennsylvania, Cullen received multiple consecutive life sentences—eleven terms in New Jersey alone—for twenty-nine murders and several attempted murders, including the cluster of deaths at Hunterdon that encompassed Mazzacco’s case. He was consigned to New Jersey State Prison in Trenton, with parole eligibility pushed so far into the future that he will never be released, and remains there to this day. Serial-killer registries and specialized crime databases now list Frank Joseph Mazzacco Jr. as one of Cullen’s victims, and there is no public record of any alternate suspect ever emerging in connection with his death; the investigation effectively ended with Cullen’s guilty pleas. In the years since, Mazzacco’s name appears less in sensational retellings of the “killer nurse” than in quieter online memorials and cemetery records, where he is remembered simply as a veteran educator whose final trip to the hospital intersected with a hidden predator moving through New Jersey’s healthcare system.
