Atlantic County Prosecutor’s Office(NEW YORK) — The message from the grave was defiant. But was it the truth?

For five years, Kim Pack suspected her stepfather, Dr. James Kauffman of killing her mother, a bubbly host of a popular local radio show. But it wasn’t until January of this year that the prominent New Jersey endocrinologist was charged with putting a hit out on April Kauffman’s life.

Before he could go to trial, Jim Kauffman was found dead of an apparent suicide inside the county jail where he was being held.

“I was stunned,” said Damon Tyner, the Atlantic County prosecutor who charged Kauffman with orchestrating the plot that ended with the murder. “But in retrospect, that’s what convinces me now more than ever that he understood the end was near.”

Bringing a stunning climax to a murder mystery that riveted the Philadelphia-South Jersey region, Tyner and his team had charged Kauffman with devising a murder-for-hire plot to kill April Kauffman after, prosecutors say, she’d threatened to expose an illegal drug ring he was allegedly running with members of the notorious biker group, the Pagans Motorcycle Club.

Kauffman was accused of working with a reputed Pagans leader named Ferdinand Augello to arrange the hit on April Kauffman after, prosecutors believe, she threatened to go public with the shocking revelation that her husband had never served in the military, though he promoted himself as a Green Beret veteran who performed acts of heroism during the Vietnam War.

“Jim Kauffman was involved with the Pagan outlaw motorcycle gang,” Tyner said. “You had a prominent endocrinologist that was prescribing opioids and all kinds of other painkillers… when that wasn’t ‘his practice.’”

April Kauffman, a vivacious 47-year-old who earned a following on the radio and as a veterans activist, was found shot dead on May 10, 2012, in the bedroom of the Linwood, New Jersey, home she shared with her husband.For years, no arrests were made in the Kauffman murder case, but her daughter from her first marriage, Kim Pack, and her attorneys continued digging for answers.

“We were talking to people that were critical witnesses to us that had not spoken to the prosecutor’s office,” said one of Pack’s lawyers, Andrew D’Arcy.

James Kauffman seemed to move on with his life. He remarried and filed to collect on April’s life insurance policy. Pack objected and sued her stepfather for causing the wrongful death of her mother.

That lawsuit would prove critical, giving Pack’s lawyers the opportunity to question James Kauffman under oath. It was the only time he was ever questioned under oath about his wife’s death.

In the deposition, the doctor talked about running into the house and seeing his wife’s body.

“I ran upstairs,” he said. “I looked inside and unfortunately saw April lying there and she wasn’t moving. … I ran downstairs, [out to the] lawn, and was hysterical and started vomiting.”

At one point, he was asked who he thought may have killed his wife. Jim Kauffman offered first that it could have been the police, then he suggested it might have been a veteran suffering from post-traumatic stress. Kauffman mused it could have been a “slum lord,” whom April had criticized, and then he mentioned the biker group.

“Also, the last choice was that it was someone in the motorcycle gang… the Pagans,” Jim Kauffman said during the deposition.

Prosecutors believe that it was less of a theory at the time and, perhaps, more of a confession.

James McClain was the previous county prosecutor who had overseen the Kauffman case for almost five years. He had been appointed to the post less than two months after she was killed. Pack said when she met with him, he said little about the case other than that it was active, making her question the efforts being put into the investigation by authorities. Through a spokesman, McClain declined to comment.

But last year, then-New Jersey Gov. Chris Christie moved McClain to a state judgeship and appointed Tyner to become the new Atlantic County prosecutor. As he entered the job in March 2017, Tyner ordered a top-to-bottom review of cold cases – something Atlantic County is known for.

Quickly, Tyner and his team made April Kauffman’s homicide a priority, and the D’Arcys turned over the deposition and other research they had done.

Tyner said there was “no doubt” in his mind that James Kauffman wanted his wife dead.

“She’s willing to expose his direct involvement with the Pagan [Motorcycle Club] in the operation of a pill mill,” he said. “If she’s willing to go to these lengths to expose him, he started thinking about ways to engage his exit strategy, you might say.”

Concerned that the Pagans could have the doctor assaulted or worse in jail, the authorities had Kauffman moved to the Hudson County Correctional Facility, just outside Jersey City, for his protection.

Then on Jan. 26, correction officers found his body in his cell with a six-page suicide note. Officials have refused repeated requests to release the note, but a copy was obtained exclusively by “20/20.” In it, Kauffman adamantly denies that he had anything to do with his wife’s death.

“I cannot live like this. I, no matter what anybody says, did not do anything to my wife,” he wrote.

The note added a claim that it was April Kauffman who had introduced him to the Pagans.

“April came to me and said would I like to go to a motorcycle rally … to meet some of her friends… I was slightly shocked to say the least that they had the colors of Pagans,” he wrote.

With Jim Kauffman deceased, Tyner’s last call for justice is to build a case against Augello. Tyner said his team has investigated the case from every angle, but said they do not believe that April Kauffman had any involvement with the motorcycle gang or Jim Kauffman’s alleged pill mill.

“I believe that, at some point, she became aware of it and I think ultimately that’s the reason why she was killed,” he said.

For Pack, it was a painful conclusion for a grieving daughter.

“I think she [April Kauffman] started to figure things out and I think that she might have had those as aces in her pocket, per se, to keep trying to use all these things as fuel to be like, ‘I want out and if you don’t, I’m going to do this,’” Pack said.

Augello, charged as Jim Kauffman’s co-conspirator, is currently awaiting trial. He is charged with first-degree murder, conspiracy to commit murder and racketeering. According to Tyner, Augello “propositioned a number of individuals to murder April Kauffman,” all of whom were either Pagans, former members or associated with that biker group.

Augello pleaded not guilty to the charges. He declined ABC News’ requests for comment on the specifics of the charges, but during a jailhouse meeting and subsequent phone calls with an ABC News producer he insisted that he is not being treated fairly and authorities have acted inappropriately.

Prosecutors allege a man named Francis Mulholland was the one who killed April Kauffman, shooting her twice, and received $20,000 in cash in exchange. Mulholland died of an overdose a year after the homicide.

In Tyner’s eyes, the case of April Kauffman’s homicide has been officially solved.

“We believe we have all the information and all the evidence that would point to who killed April Kauffman,” he said, “why she was killed and who participated in the conspiracy.”

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