CHICAGO (CBS) — A group of Chicago police officers headed to Springfield Thursday, to argue against parole for two convicted cop killers.

WBBM Newsradio’s Regine Schlesinger reports anytime an inmate convicted of killing a Chicago police officer comes up for parole, officers go to the Illinois Prisoner Review Board to stand for the fallen.

READ MORE: IDES Kept Offices Closed While Many Struggled To Get Their Unemployment Benefits: What Really Happened Inside And Outside Those Walls

“We’re going representing the friends and the family members who have been without these officers,” said Chicago Police Sgt. Francis Iglinski.

Both cases up before the board on Thursday date back decades: the 1967 shooting death of Officer Herman Stallworth, and the 1976 murder of Officer Terrence Loftus.

“Stallworth was killed 46 years ago. Loftus was killed 37 years ago. That’s birthdays, holidays, celebrations that their families never got to have with them,” Iglinski said.

Joseph Hurst, now 69, originally was sentenced to death after he was convicted of killing Stallworth during a traffic stop on the South Side. His sentence was later changed to between 100 and 300 years during a moratorium on the death penalty in the 1970s

READ MORE: Chicago Weather: Lakeshore Flood Threat Continues

He also was convicted of trying to kill Stallworth’s partner, officer Eugene Irwin, during the same traffic stop.

Ronnie Carrasquillo, now 55, was convicted of killing Loftus, who was trying to break up a gang fight on the Northwest Side, while off duty in October 1976.

“Carrasquillo came out of another residence, and fired a gun in the direction of the officer standing there, and struck Officer Loftus,” Iglinski said.

Carrasquillo is serving a 200 to 600 year sentence. Both Carrasquillo and Hurst are being held at the Dixon Correctional Center

MORE NEWS: Climate Change And Chicago's Lake Michigan Shoreline: What The Future May Hold And The Action Being Taken

Chicago police officers will testify against both inmates’ release, arguing they should spend the rest of their lives behind bars for killing a police officer.