PHILADELPHIA The suspected killer stewed in Interview Room D as detectives prepared charges against him in a crime that he could not escape - the five-year-old killing of Beau Zabel.

Marcellus Anthony "Ant North" Jones had been "mouthy," as one detective put it, during Wednesday morning's drive from Graterford Prison to Police Headquarters.

Investigators had retrieved Jones so they could book him in the 2008 killing of Zabel, a teaching student from Minnesota gunned down for his iPod near the Italian Market as he walked home from his night shift at a Starbucks.

The killing of a young man who had come to Philadelphia just six weeks earlier to teach math in the inner city pulled at the conscience of the community five years ago.

Now, in the cramped confines of the Homicide Unit, there would be another step toward justice.

To prepare Jones to be charged with murder, prison guards removed the face mask that the 35-year-old is made to wear to keep him from spitting on people. At the Homicide Unit, Jones - who is serving a life term after a 2012 conviction for killing a 19-year-old accomplice in the Zabel slaying - shouted when a detective took him to the bathroom.

He was innocent, he said. He had been wrongly convicted the last time around. Where were his rights?

"I'm another Trayvon Martin," he said.

Sitting in a cramped office, Lt. Mark Deegan of the Special Investigation Unit shook his head.

"We go through this a lot," said Deegan, who has been working homicides for 15 years. "He is trying to make himself the victim."

But Deegan and the other investigators who have worked the Zabel case over the years have long known Jones to be something else entirely: a remorseless killer.

"This is one of the ones where you get a lot of satisfaction," Deegan said. "This guy Marcellus Jones is a thug."

Deegan has been the supervisor assigned to the case from the beginning. He had been at the crime scene on Ellsworth Street that night in June 2008 where police found the 23-year-old Zabel dead eight houses from his apartment, his eyes open and the pants pocket where he kept his iPod turned out.

The senselessness of the killing was never lost on the veteran investigator.

"This was a kid - a young guy who wanted to give of himself," Deegan said Wednesday. "He wanted to come to Philadelphia to help, and you don't hear that story very often. That's not something that happens every day."

Deegan remembered sitting in his office a year and a half ago, expressing hope that the case could be solved. Jones had just been convicted for killing Tyrek Taylor, his suspected getaway driver, whom prosecutors said he killed to keep him quiet about the Zabel murder.

Police didn't have enough to charge Jones then, Deegan said. With so much time from the slaying, there was no chance of finding the gun or Zabel's iPod. Investigators needed one more witness whom Jones might have discussed the killing with - that would be the only thing that could bring the case in, he said.

On Wednesday, Deegan credited an Inquirer series published on the five-year anniversary of Zabel's death as providing the spark that helped investigators get the evidence they needed.

That break came last month when an acquittance of Jones' stepped forward and told detectives he had heard Jones speak about killing Taylor and "the teacher in South Philly" shortly after the crimes during a gathering at a house in Germantown. He said Jones had killed Zabel because all he had on him was an iPod rather than an iPhone.

The man said other witnesses had heard Jones, too.

One of those witnesses then told investigators that they had realized Jones was talking about Zabel after reading the "article in the newspaper" this year, Deegan said.

"The story, it was kind of like proof for them," Deegan said of the Inquirer series. "When they [the witnesses] read the story, it was like, 'A-ha. We're right. We thought it was that teacher.'

"It confirmed for them what they already knew," Deegan said.

An arrest warrant for Jones was issued last month based on the new evidence and testimony of Devonne Brinson, who testified at the 2012 trial that Jones had told him about killing Zabel.

All that was left was to work out the logistics of getting Jones from the state prison to Philadelphia. That happened Wednesday.

Besides shouting, Jones refused to speak to investigators, Deegan said.

Having been convicted of murder already, he could face the death penalty. That lies ahead at trial.

After detectives were done with Jones, there was one more thing to do.

Detective George Fetters - who had worked the case with Deegan from the start - made a call to Zabel's family in Minnesota.

"I'm happy to say we've arrested the man who killed your son," he said. It was a call he had long wanted to make.

mnewall@phillynews.com

215-854-2759 @MikeNewall