Authorities gave contradictory accounts Thursday of why Jones, who had three previous arrests as an adult on assault or illegal-gun-possession charges - and who served four years in prison on the gun conviction - was permitted to walk out of jail unmonitored. At the time, he was being held for violating probation in February after he was charged with a gunpoint robbery.
Two Nutter administration officials and a court-system spokesman offered conflicting explanations for Jones' unmonitored release.
The prosecutor in the July 25 probation hearing had urged Common Pleas Court Judge Susan I. Schulman to place restrictions on Jones before freeing him, according to Tasha Jamerson, a spokeswoman for the District Attorney's Office.
Schulman that day ordered Jones "released on State House Arrest with electronic monitoring," according to court documents.
But Jones was not immediately released, for reasons that remain unclear.
Shawn Hawes, a spokeswoman for the Philadelphia prison system, said Schulman ordered prison officials to release Jones Aug. 8 without monitoring.
Schulman declined to comment when reached by an Inquirer reporter Thursday.
Frank Keel, a spokesman for the court system, said the First Judicial District was "concerned that Judge Schulman's order . . . was not effectuated."
Keel said the court system "will release further information when we determine why Judge Shulman's order was not followed. . . . All of us want answers and are working to ascertain them as quickly as possible."
Mayor Nutter's spokesman, Mark McDonald, insisted that the city prison system complied with the order.
McDonald did not explain why Jones walked out of prison without electronic monitoring. He said Jones was not freed until two weeks after the judge's order because "officials desired to check with the judge." But he did not say whether the judge had been contacted personally.
"We checked to make sure we were doing what the judge wanted," McDonald said, declining to identify the person contacted.
Jones had no GPS device tracking his movements on Saturday, the night police say he and an accomplice stalked Walker, off-duty and in civilian clothes, and shot him dead in a robbery attempt.
U.S. marshals took Jones into custody Wednesday at a public-housing complex in Southwest Philadelphia on a bench warrant for failing to report to his parole officer.
As of Thursday night police had yet to charge Jones in the murder. Philadelphia Capt. James Clark, head of the homicide unit, continued to say Thursday only that police were interviewing a "person of interest" but that he believed the man in custody was Walker's killer.
"We believe charges are forthcoming," Clark said.
Police have not publicly identified Jones, but investigators have confirmed his identify.
Questions remain as to how Jones, the kind of offender city leaders have said they want to keep off the streets - he has a record of violence and guns - managed to slip out of reach.
John McNesby, president of Fraternal Order of Police Lodge 5, said he was not surprised to hear the circumstances surrounding Jones' release.
"The whole system is broken," he said. "It's a bureaucratic mess. A very small portion of judges are willing to stand behind police and keep these people in jail, and we're now planning another funeral for a police officer."
Walker was the fourth officer killed this year while off duty.
A 19-year veteran of the force, he had just finished his night shift at the North Philadelphia-based 22d District shortly before 6 a.m. and was walking to a bus stop in the 2000 block of Cecil B. Moore Avenue. Surveillance video released this week showed two men walking nearby, then apparently spotting Walker. Other footage captured Walker glancing over his shoulder toward the men, who followed and caught up to him.
They stopped him and announced a robbery, police said, and as Walker tried to draw his off-duty gun, he was shot in the chest, the stomach, and one arm.
A reward posted for information leading to his killers grew to $118,000. Police have not said whether anyone could collect the money.
A tip led officers to the Bartram Village complex, where they found Jones, police said. On Thursday, investigators continued combing the area for additional evidence.
Court documents indicate that Jones started getting into trouble with the law when he was a juvenile, but details were unavailable.
In September 2007, Jones's sister told police that Jones, then 18, had slapped her during an argument and waved a gun at her. He was arrested the following month and accused of trying to kick in the door to his mother's Powelton Village home. Police caught him after a brief chase and found a loaded handgun, a black ski mask, and eight bags of marijuana on him, according to court records.
Jones landed in jail, but records show that prosecutors dropped most charges in January 2008 after his sister did not show up to testify. He was convicted of illegal gun possession, records show, and was sentenced that April to two to four years in prison with three years of probation.
Department of Corrections spokeswoman Susan McNaughton said Jones spent nearly six months in a Philadelphia jail and served the remainder of his four-year sentence in state prison. He was released in October 2011.
In February, Jones was arrested on charges of armed robbery. According to court records, Jones and an accomplice were accused of holding up a man at gunpoint in Germantown and stealing his jacket, cellphone, earphones, and $34. But the man failed three times to appear for court, and two months later, prosecutors withdrew the case.
The Feb. 13 arrest was for a violation of Jones' state probation resulting from his 2008 conviction on firearms charges. By the time of his July 25 probation violation hearing, the charges had been withdrawn.
Although Jones had also been charged with firearms counts, Jamerson said no gun was recovered, just proceeds of the alleged robbery.
Assistant District Attorney Maureen Holland, who prosecuted the case, was unavailable for an interview, but Jamerson said the sequence of events she described was based on her conversation with Holland.
Although Jones' 2008 sentence had run its course, Jamerson said, his arrest was a technical violation of his state parole on the charges. An unidentified parole officer was at the July 25 hearing, and Jamerson said Holland urged the judge to place restrictions on Jones, whom she considered "intimidating."
"She said she heard him telling a codefendant, 'Don't say anything. Don't be a rat,' " Jamerson said.
Although Jones' public defender, Rosemary Zeccardi, opposed placing Jones on house arrest, Schulman ordered that he serve electronically monitored house arrest for at least six months, complete community service and a GED program, find and hold a job, and submit to weekly drug screens.
Zeccardi was on vacation Thursday and could not be reached for comment.
Jones remained in custody in the Philadelphia prisons after the July 25 hearing until Aug. 8, according to Hawes, of the city prison system. At that point, Hawes said, Jones was released and instructed to see his probation officer.
It is not known if Jones reported to his probation officer of his own accord, or where he went, until Philadelphia police took him into custody.
"There was no GPS," Jamerson said. "This man was walking around because he did not have GPS monitoring."
Sherry Tate, director of the Office of Policy, Legislative Affairs and Communications for the state Board of Probation of Parole, said the conditions under which a state probationer is released is considered personal information. Tate said the judge decides the conditions, and the board follows the judge's instructions.
Tate called Jones a case of "special state probation" because his sentence had run its course and his state probation had been extended on the orders of a Common Pleas Court judge.
Contact Mark Fazlollah at 215-854-5831 or firstname.lastname@example.org.
Inquirer staff writer Robert Moran contributed to this article.