The vehicle-tracking operation was a covert measure by the Somerset County Prosecutor’s Office to monitor Charles Cullen when investigators believed he posed an ongoing danger but could not yet prove a charge against him. Rather than arrest him on suspicion alone, detectives arranged for a radio-tracking device to be concealed in his car and followed his movements from a distance while they tried to build a prosecutable case.

Why the Detectives Could Not Arrest Him

By this point, the investigation had exposed a troubled work history that included at least three previous investigations and possibly a fourth, as well as a personal history that included perhaps a dozen suicide attempts and at least one arrest. The detectives were convinced Cullen was a killer, but conviction was another matter: they had not definitively connected him to a crime at Somerset Medical Center. Arresting him prematurely, they feared, would alert him to the surveillance; he could contact a lawyer and soon be back on the street.

The potential cases against him were serious but incomplete. Investigators were considering Reverend Florian Gall as a murder victim and Jin Kyung Han as a possible attempted-murder victim, and medical opinion indicated that both had received deadly levels of drugs. Yet the presence of victims, drugs, and a suspect did not establish who had administered them. Investigators could not trace a drug to a particular syringe and its user as they might trace a bullet to a gun.

The Pyxis system seemed to offer a way to establish access, but the hospital had told detectives that it retained medication data for only thirty days. Reverend Florian Gall had been dead nearly four times that long, leaving the relevant records apparently unavailable and the case stalled. The tracking operation addressed the immediate problem of monitoring Cullen; it did not, by itself, resolve the evidentiary gap.

The Covert Installation

The detectives’ plan began with a deliberately false traffic pretext. Charles Cullen was held up over a bogus parking-ticket problem while investigators worked on his impounded Ford. Under a judge’s order, Danny Baldwin and Tim Braun had arranged the operation legally; detectives unscrewed the car’s door panel and installed a radio-tracking unit inside.

The hidden device changed the investigation from a series of uncertain glimpses into continuous surveillance of Cullen’s movements. An unmarked car followed at a safe distance, with one detective from the Major Crimes Unit and another from the Narcotics Squad rotating shifts around the clock. The arrangement was designed to keep watch without confronting or warning him.

Surveillance as a Holding Strategy

The operation reflected the investigators’ predicament: they believed Cullen had harmed patients, but suspicion could not substitute for proof, and an early arrest might only give him notice that he was being watched. The tracker let them contain some uncertainty about where he was while they continued seeking evidence that could support action against him.

Its limits remained clear. The device could follow a car, not establish who had poisoned a patient or reconstruct a missing medication record. The detectives still needed to connect Cullen to at least one killing or attempted killing before they could stop him through an arrest. The surveillance therefore served as an interim safeguard during a case that the investigators feared was unfinished and potentially still dangerous.