Rafael Jones, 23, was charged by police on Friday morning in the death of Officer Moses Walker, Jr.
Investigators say Jones was one of two men seen in surveillance video, released by investigators as they searched for suspects.
The other man in that video remains at large.
Overnight, sources told Action News that police questioned Jones' younger brother, but stress he is not a suspect. Police say they questioned him to gain more information about the second suspect.
Jones had been under intense questioning by homicide investigators and, at first, was refusing to cooperate or answer any questions. Apparently, that changed Thursday night, as word has come in that the male gave police new information they otherwise did not have.
Jones was taken into custody on Wednesday and Action News has learned that he has a lengthy criminal history.
Court records reveal that, in 2007, he allegedly slapped and pulled a gun on his own sister. However, she refused to testify and the charges were dropped.
A few months later, in 2008, Jones was sentenced to two-four years in prison on firearm charges.
After serving his time, he was arrested last year for allegedly pulling a gun on a man, stealing his jacket, cash, mobile phone and other items. The alleged victim failed to show up in court. The charges were dropped.
However, the arrest was a clear violation of his parole. So, in March, a judge ordered him to court.
The judge continued Jones' probation, which included earning his GED and weekly drug tests with one added requirement: state electronic monitoring.
It's unclear what happened to the electronic monitoring, but the 23-year-old, from North Philadelphia, is now in custody on a bench warrant for failing to appear at the probation department.
Police are still searching for his accomplice, but say they know who they are looking for.
"Anyone who is out there that is helping him, or knows who he is, need to contact the homicide unit and turn him in," said Capt. James Clark of the Philadelphia Police. "We are interviewing other people who may have heard something or seen something, whatever, but eventually we will get enough to bring charges.
Officer Walker, a 19-year veteran had survived his shift in the 22nd Police District, only to be gunned down in civilian clothes during a robbery attempt as he walked to a bus stop near 20th Street and Cecil B. Moore Avenue.
If you have any information about the suspect or the crime you can submit a tip by dialing 215-686-TIPS (8677), text TIP to PPD TIP (773847) or through phillypolice.com.
Funeral for Ofc. Walker planned
Police would like to have both men in custody and wrap this case up before the officer's viewing and funeral on Sunday.
The viewing for Officer Walker will be held on Sunday, August 26, at Deliverance Evangelistic Church, located at 2001 Lehigh Avenue in Philadelphia starting at 6:00 p.m. until 10:00 p.m.
On Monday, August 27, from 7:00 a.m. until 10:00 a.m., a public viewing will be held at the Deliverance Evangelistic Church.
Funeral services will begin at 10:00 a.m.
Committal Services will be held following the service at Fernwood Cemetery, located at 6501 Baltimore Avenue in Lansdowne, Pa.