Jackson faces unrelated robbery charges in New Jersey, which could delay his extradition, a source involved in the investigation said.
"There was a perception [among the suspects] that there were drugs involved, and where there's drugs, there's money," Heckler said.
It was possible the men "knew him or knew of him," Heckler said.
DeGennaro, 56, was shot once in the chest at short range with a shotgun in the rear of his Bristol Township house about 10 p.m. Dec. 28.
He made his way to the front of the house, where he collapsed into the arms of a man who rented the lower level of the house, Heckler said.
The popular guitarist and songwriter, who played with such rock and R&B stars such as Bob Weir of the Grateful Dead and Clarence Clemons of the E Street Band, died a short time later at St. Mary Medical Center.
Police do not know which suspect shot DeGennaro, Heckler said. He could not say whether the shotgun and 45 mm handgun that were used have been recovered.
According to court documents, Jackson told the two men and two young women "that they were going to a guy's house that owed him money. Jackson wanted to go and try and get the money, but if there was any problem, Jackson was going to have Powell come in and hold the guy at gunpoint while the guy gave Jackson the money."
Investigators don't know whether DeGennaro owed money to Jackson or the other men, Heckler said.
The women, Danasia Bakr, 17, of Falls Township, and Tatyana Henderson, 18, of Bensalem, face the same charges as the men. Bakr is being held without bail in Bucks County Prison and faces trial as an adult, and Henderson is being held on unrelated theft charges. She will be arraigned on the other charges, Heckler said.
In interviews with police, Bakr admitted her involvement in the killing and gave this account, according to court documents:
The five suspects drove from Trenton to DeGennaro's neighborhood that night and drove around for an hour. Henderson tried to lure DeGennaro out of his Crabtree Drive house by calling the phone number on a Volkswagen Jetta for sale in the backyard, but the car and phone number belonged to a neighbor who refused to show them the Jetta.
While Bakr and Henderson waited outside, the men went into the house. Bakr then heard a loud gunshot, followed by a second gunshot. As she started to drive away with Henderson, Powell and Gist pounded on the trunk and jumped into the car.
"Powell said, 'I had to do it' because the guy had charged at him," Bakr said. "Gist was saying that he shot him too."
The four returned to Trenton, where they met up with Jackson. When Powell got out of Bakr's car, he removed a shotgun from his pant leg, took it apart, and put it in a gym bag.
Heckler said it was too early to determine whether he would seek the death penalty in the case.
DeGennaro's daughter, Gia, was "relieved" when told about the arrests, Assistant District Attorney Matt Weintraub said.
"She's preparing herself for the long legal road ahead."
Contact Bill Reed at 215-801-2964, firstname.lastname@example.org, or follow on Twitter @breedbucks. Read
his blog, "BucksInq," at www.philly.com/bucksinq.