Graeber wrote the book The Good Nurse: A True Story of Medicine, Madness and Murder, which details Cullen’s early life and the murders he committed while working as a nurse from 1988 to 2003 in nine hospitals.

The serial killer is currently serving 18 consecutive life sentences for the deaths of 29 patients, though authorities believe he killed 400 people.

Charles Graeber on How Charles Cullen Felt Murders Were ‘Pointing Out Hypocrisy’

Describing himself as a mercy killer was something that “stuck with” Cullen when he was being interrogated by Detectives Tim Braun and Danny Baldwin, the author explained to Newsweek.

“He is so easily confused in the public eye as a mercy killer because we’ve seen that sort of thing before […] it’s easy to understand why one might, when you see the suffering that goes on in some of those wards, believe that death is a blessing and think that might be a merciful act,” Graeber said. “[But] the murders had everything to do with what he needed at that moment and what worked for him, and absolutely nothing to do with those people.”

Graeber added that though Cullen has sometimes been made out to be a mercy killer, when he spoke to him he “learned that narrative was wrong, false and incomplete.”

“He doesn’t think he was a mercy killer, that [explanation] was convenient. There are different ways of trying to explain why he did it. One of them, of course, is that there’s no answer,” the author said.

“Another is that it worked for him, it really meant something different to him and depending on the circumstances in his life—whether his marriage was falling apart, whether the custody hearing for his children were going badly, he had felt wronged or disrespected in some ways in his personal life, or simply wasn’t feeling the spotlight of the universe was enough upon him—This was a way of sort of giving himself a little pick me up, and it really was that simple.

“One final thing about why, when I spoke to him he sort of paused when we got to something like that and said ‘well, it depends on what you think people are capable of’ when I was asking about motivation.”

“The fact that the hospitals, in his view, knew what he was doing and knowingly passed him on so that they didn’t have to deal with the liability of it, he thought that was the height of hypocrisy and that in some way the fact that he was able to continue to do what he did was almost justified,” Graeber went on.

“It was almost a way of pointing out the hypocrisy of these places that were supposed to be wonderful, caregiving facilities where the vulnerable are protected […] the fact that they acted in this manner made him feel like he was almost a living critique of the hypocrisy.

“But, this is all about his mindset, which essentially takes no real responsibility for, or puts that responsibility on other people and other institutions, but it’s absolutely not a mercy thing.”

Graeber’s first meeting with Cullen was a “strange one.” The author was the only journalist that Cullen agreed to speak to after he contacted Cullen over his desire to donate a kidney to the dying relative of an ex-girlfriend for an article he wrote for the New York Magazine in 2007.

Their conversations began “in secret” with Graeber also speaking to Cullen’s lawyer and priest, and when they did finally meet in person both parties felt “almost mutually embarrassed,” Graeber said.

“My take was ‘I’m sorry, I have to come and ask you these awkward questions’ and he was sort of like ‘I’m sorry, you have to come all this way, go through a metal detector and all these things and find me in jail clothes.’

“He was charming but self-deprecatingly so, funny, insightful, quiet but he’s also a sociopath so he matches your expectations and your mood when he’s at his best. That was the initial tone of our conversations, but that tone wasn’t consistent.”

There were subjects that Cullen “loved to talk about” like his mistreatment in the navy or what he perceived as bullying at work, while others that made him almost switch off in Graeber’s presence, the author said.

“If I let him go [on], which I tried to do, each time I would get another layer, if you will,” Graeber said. “By shaving around the edges of things I learned a little bit more about what had happened in his childhood home with his siblings, with his mother, things like that, or I would compare stories for consistency and then be able to follow up.

“But to go directly at anything like exactly what was happening in that house was a no go, to talk directly about murder was a no go. He would sometimes, if we got there, say that he felt compelled to act or compelled to intervene or something just happened. But, for me to go right at his motives, or his direct action against someone, killing someone, it was almost as if you sprayed him in the face with water, he would freeze.”

Describing how Cullen would shut down on him, Graeber added: “If I tried to gradually bring us to that place I could see his attention sometimes fixating on a corner of the table, or something like that, more and more of him leaving and going somewhere else dark.

“And sometimes he would terminate the conversation if we went that far, it would take some weeks before I could get him to show up again. It was hard, it’s difficult to communicate with someone when they’re in those facilities and that setting, so I never really knew what to expect.”

While in the prison Graeber was unable to record any of his conversation with Cullen, in fact oftentimes he would have to commit everything they had spoken about to memory.

“I was just trying to be a sponge and present, and then I would get, for instance, out between the barbed wire and ducked between the vehicles in the dark parking lot of Trenton prison, where you’re not supposed to be on a phone, they have a lot of rules that you can imagine for going in or being near this maximum security facility,” Graeber explained.

“And I would hold up my tape recorder to my head as if I was making a phone call and I would just regurgitate verbatim everything I had seen or everything he has said in almost a stream of consciousness and try and get that out of me, and then on the way home I would just feel shaken… it was a really exhausting process.”

He went on: “My ability to record was limited to a few sessions where I was able to join Cullen by video link through his lawyer because I could have a recorder in the lawyer’s office.

“But there weren’t very many of those and they were really brief and he had guards yelling at him and kind of abusing him through the doors and during that he didn’t feel open to talk and it was not particularly intimate so that wasn’t very useful.

“When in jail I could bring in a pencil at least and write something down and record everyone else around him, but when it came to seeing him for the most part what I had to do was just empty my mind and try to capture not only the facts but his cadence and his bearing, and be my own recorder.”

Graeber’s book is the inspiration for the Netflix film The Good Nurse, which stars Eddie Redmayne as Cullen and Jessica Chastain as the nurse who helped persuade him to confess to police, Amy Loughren. Cullen’s actions are also set to be the subject of the documentary Capturing the Killer Nurse, which Graeber has executive produced and stars in.

Through these projects, Graeber hopes that those who chose to pass off Cullen to other hospitals will finally be held accountable for indirectly allowing him to keep killing patients.

“The families of the known victims, all those families settled and signed non-disclosure agreements and so they can’t speak so, really, I have to speak for them,” Graeber reflected.

“When I first started talking to the detectives, or they first agreed to speak with me, they were really hesitant to do so and they didn’t necessarily trust the press […] and when they understood the depth of my conviction, over the course of seven years, they said that they really were spending so much time with me, and agreeing to be so honest, and tell me their story as they knew it because they wanted further justice.

“They asked for a grand jury at the end, after Cullen had been arrested. A grand jury to examine the role that the individual institutions, the gatekeepers, the managers, the CEOs had played in intentionally, or otherwise, protecting Cullen, facilitating Cullen, passing him on to an unsuspecting hospital.

“That request for grand jury was denied, it was a political decision. The powers that be in those communities didn’t want to make things worse, didn’t want to stir up additional problems for local hospitals that they depended on.

“I honestly believe that with more and more people understanding what happened and asking questions that political will may change, and that we may indeed at least get to a grand jury to be able to ask those frank questions and get some answers on the record.

“And there is no statute of limitations for accessory to murder, so there’s still an opportunity to have real consequences on the back of those questions.”

Charles Graeber’s book, The Good Nurse: A True Story of Medicine, Madness, and Murder, is available now. Additionally, the documentary Capturing the Killer Nurse will be released via Netflix on November 11, while the feature film The Good Nurse is currently streaming on the same site.