The wrongful death and civil rights lawsuit argues that the alleged killer of Officer Moses Walker Jr. should have been behind bars.
Investigators said Rafael Jones, 23, was released from prison 10 days before he and another man allegedly shot and killed Walker on Aug. 18 during a robbery as the officer walked home in street clothes after his shift.
Walker, 40, was able to draw his weapon before he was shot three times, police said.
The lawsuit filed Tuesday contends Jones was supposed to be under electronic monitoring and failed a probation office drug test but wasn't taken into custody as a judge had ordered.
"The probation and parole system failed Officer Walker, a valiant law enforcement officer, and we now turn to the federal court system for justice in his name on behalf of his survivors," said attorney Michael F. Barrett, who filed the suit on behalf of the officer's family.
Walker's mother, Wayne Lipscomb, called her son "every mother's dream come true: a good man, a kind, caring and gentle man, deeply devoted to our family, his friends, fellow police officers, and above all, his faith."
"We honor Moses when we asked our lawyers to do everything possible to make sure that what happened to him never happens to another human being," she
A message left for a spokeswoman of the probation and parole board was not immediately returned Tuesday.