A tip in the search for missing man Keith Palumbo led investigators to a cemetery crypt — and a gruesome discovery inside.

The haunting case of the 36-year-old Delaware County, Pennsylvania, musician and tattoo artist, who was murdered by his longtime friend, is now the focus of Oxygen’s true-crime series, “Philly Homicide,” where retired detective Chris McMullin revisits some of the city’s most explosive crimes.

“This is a very sad case,” McMullin told Fox News Digital. “Through a very thorough investigation involving interviews with other parties that either had knowledge or some type of involvement, it led them to Mount Moriah Cemetery. And honestly, it was not that surprising to me because I know that a lot of stolen cars have been dumped there.”

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“I even say in the episode, if you wanted to hide a body, that’s probably a good place to do it,” said McMullin, describing it as “a cemetery that nobody was really taking care of.”

In April 2020, investigators unearthed not only Palumbo’s body, but also the remains of David Rossillo Jr., 33, a prospective member of the Warlocks Motorcycle Club. Both victims were found in the family vault of Capt. A.H. Cain, who died in 1884. Rossillo’s killing was a separate incident, though his remains were discovered in the same crypt.

McMullin said that Mount Moriah Cemetery had fallen into disrepair for years and was largely abandoned. According to reports, it had become a known dumping ground for stolen cars and other illegal activity.

“Mount Moriah Cemetery had gone out of business years ago,” McMullin said, referring to its long period of neglect.

“I’ve been there. There was a time when I worked part-time in the funeral business and I was there. It’s something like out of a post-apocalyptic film when you go there. There are headstones that are knocked over and vines growing all over mausoleums. It’s very sad because this was a cemetery where people were laid to rest. Typically, you expect it to be cared for perpetually.”

“We’re also talking about a huge cemetery,” McMullin continued. “[The investigators] got lucky because, as they were walking around, they noticed that one of the crypts seemed to have been recently disturbed.”

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Palumbo was described as coming from a close family and was known in his community for being a heavy metal guitarist. When he went missing in February 2020, his family immediately knew something was wrong.

At the time he went missing, Palumbo was driving his mother’s car with two other men when he received a phone call from his friend, Warlocks member Michael DeLuca, who went by the nickname “Kaos,” The Philadelphia Inquirer reported. According to the outlet, DeLuca had told Palumbo to go to his Southwest Philadelphia home.

“When I learned that he had gone missing, it just gave me an ominous feeling,” said McMullin. “All the cases we explore in this series are tragic, but this was such a case of betrayal.”

The outlet reported that after the three men arrived at DeLuca’s apartment, he pulled out a handgun and pointed it at Palumbo. While Palumbo protested, a witness told investigators that DeLuca shot him in the face. The outlet noted that the account was cited by one of the men who was said to be in the apartment at the time.

McMullin said that while the circumstances of the argument were unclear, authorities and witnesses suggested DeLuca may have suspected Palumbo of cooperating with law enforcement, though no evidence was presented to support that claim.

“I don’t know if we ever got a specific answer from DeLuca,” McMullin admitted. “It was speculated that he may have done it to set an example not to cross him. This victim was his lifelong best friend. Was he trying to make an example for the other members? It certainly seemed like they were afraid of him.”

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“I do think there’s probably an issue with impulse control there,” said McMullin. “I do think that this was calculated and planned. They more than likely took [Palumbo] to the clubhouse with the intention of doing that to him.”

While the Warlocks may not carry the same name recognition as groups like the Hells Angels, authorities have long identified the Pennsylvania-based club as a serious outlaw motorcycle gang.

Federal and local investigators have tied members to a range of violent crimes, including murder, assault and drug trafficking, a reminder that a lower profile does not mean a lesser threat.

“The other organizations are much larger and they show up in places that get more public attention and media attention, versus a smaller organization like the Warlocks, where they’re not fully national in scope,” retired ATF Special Agent in Charge Bernard Zapor explained to Fox News Digital.

“Some gangs are purposely more low-key,” he said. “They’re not interested in all the publicity and notoriety. “[But] they all have a similarity in that betrayal of the organization is a death sentence. You have allegiance to the club first, and then your family comes after that. It’s club before family, club before self. And the suspicion of being an informant is dangerous and unfortunate.”

“These two people knew each other, had a longtime relationship,” Zapor continued. “But if you’re suspected of being a police informant, the only outcome is death. It’s a death sentence if they can get to you.”

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A relative of Palumbo’s has said that he was not a Warlocks member.

According to the episode, cooperating witnesses ultimately helped police piece together what happened to Palumbo and Rossillo Jr. The information, combined with physical evidence recovered at the scene and cellphone data, allowed investigators to build a case against DeLuca and others.

A witness told police that DeLuca said he killed Palumbo and needed help disposing of the body, The Philadelphia Inquirer reported.

“They were all afraid of [DeLuca],” said McMullin. “But I also think that when push came to shove, they didn’t want to lie and possibly risk taking a prosecution to protect him. I just think there’s no honor among thieves. Loyalty is something made very clear that’s expected. But I also think that people are also out for themselves, especially people who are committing a lot of crimes, heinous crimes at that.”

In September 2020, DeLuca and Michael DiMauro, another member of the Warlocks, were arrested.

In 2023, DiMauro was found guilty of first-degree murder and abuse of a corpse in connection to Rossillo Jr.’s death. Prosecutors said he shot the 33-year-old, tied a rope around his neck and dragged his body to the crypt, which had been pried open, before dumping the remains. He was sentenced to life in prison without the possibility of parole.

That same year, DeLuca pleaded guilty to third-degree murder in Palumbo’s death, FOX 29 Philadelphia reported. Three others also pleaded guilty to helping to dispose of the victims’ bodies, the outlet shared. DeLuca was later sentenced to 15 to 35 years in prison.

“This case stayed with me,” said McMullin. “There’s the relationship between the killer and the victim. Although sadly, more people are killed by people they know than people they don’t know. And outlaw biker gangs are notoriously violent. Michael DeLuca, in my opinion, did an evil act.”