One of America’s most notorious serial killers could have dozens or even hundreds of uncounted victims, a Kane In Your Corner investigation finds. And one detective, who says she tried to identify potential victims, says her efforts were shut down by superiors.

Charles Cullen, a former nurse, is serving life in prison for murdering 29 patients at hospitals across New Jersey and Pennsylvania. Some investigators have long suspected Cullen of killing many more patients. Tim Braun, who headed up the 2003 investigation that led to Cullen’s arrest, has estimated that the death toll could even reach “multiple hundreds.”

Harry Frasca and John McKernan could be among Cullen’s uncounted victims. They died at Saint Barnabas Medical Center – now known as Cooperman Barnabas Medical Center - in 1989 and 1991. Cullen was involved in caring for both. Their deaths were ruled heart attacks, but both families say there were suspicious circumstances.

“They told me it was a heart attack, and I said, ‘That doesn't make sense,’ says Frasca’s daughter, Barbara Lamanna. “How do you go into convulsions with a heart attack?”

McKernan’s son, Brian, notes that his father had high levels of digoxin, a powerful heart medication, in his system, but says, “he wasn't taking digoxin. We didn’t even have digoxin in the house.”

Digoxin is one of the medications Cullen most often used to poison victims.

Several relatives say they believe prosecutors lost interest in pursuing the case further after they obtained 29 guilty pleas. Lamanna says when she asked the Essex County Prosecutor’s Office to revisit her father’s case, the person she spoke with didn’t seem interested.

“He said, ‘Am I supposed to give him another life sentence?’” Lamanna recalls. “And I said, ‘Isn't that your job?’ Like, yes, you're supposed to give him another life sentence. If he killed my father, you're supposed to give him another life sentence.”

In 2023, Kane In Your Corner learned that the Essex County Prosecutor briefly reopened the Cullen case.

“We received information that there was a potential victim of Charles Cullen and we began our investigative efforts,” says Aileen Clowes, the former cold case detective who oversaw the investigation.

Clowes says she was quickly shut down by superiors. “I was told by the captain... that I was no longer to work on the investigation,” Clowes says.

Kane In Your Corner asked the Essex County Prosecutor’s Office why the 2003 investigation was called off. A spokesman declined to comment, saying, “There is no statute of limitations for the crime of murder under New Jersey law. For that reason, this matter remains subject to potential prosecution, and we cannot provide further information or comment.”

Walt Kane will take an in-depth look at Charles Cullen’s uncounted victims this Friday, in an episode of Crime Files. Uncounted: The Unknown Victims of Charles Cullen airs Friday at 9:30 p.m., only on News 12.