The family of a slain Philadelphia police officer is suing the Pennsylvania Board of Probation and Parole.

The family says the death of Moses Walker could have been prevented.

Walker's family filed the civil suit in federal court, charging the board failed to do its job. The Walkers' attorney, Michael Barrett, says the man accused of killing Walker, Rafael Jones, should never been on the streets. Jones had failed a drug test and did not have the phone line necessary for his house arrest ankle bracelet to work

"Rafael Jones did not have a telephonic landline placed at his residence and was not being monitored electronically as of Aug. 18, 2012, when he murdered Officer Walker in cold blood," Barrett said.

Barrett says parole agent Juan Rodriguez had asked for an arrest warrant, but it was denied. Barrett says if it had been approved, Jones could have been taken into custody before the shooting.

The suit names two women it says denied the arrest warrant request, claiming they neglected the "board's obligations and or duties with respect to supervising the probation or Rafael Jones."

Fraternal Order of Police head John McNesby says this isn't the first time this has happened in Philadelphia.

"Had policy been followed, had the orders been followed. Moses Walker would be alive today. Same thing in 2007 had policy been followed, had orders been followed, Pat McDonald would be alive today," McNesby said of another slain officer.

Daniel Giddings gunned down McDonald shortly after he was paroled under an early-release program. Giddings had fled a halfway house and was involved in an assault on another police officer before he shot McDonald to death. Giddings was then shot and killed by police.

The suit in the Walker death seeks unspecified damages. McNesby of the FOP says he hopes the case will shine a spotlight on problems in the system.

A spokesman for the Board of Probation and Parole says they have not gotten the suit and cannot comment.