CHICAGO (CBS) — A busload of Chicago police officers headed to Springfield Thursday to oppose parole for a convicted cop killer.

The case is 45 years old. In December of 1967, plainclothes patrolman Charles Pollard was found shot to death in an alley behind his home at 21st and Pulaski.

His empty wallet was found near his body and his service revolver and watch were missing, WBBM Newsradio’s Regine Schlesinger reports.

Clifton Hill, just 19 years old at the time, was one of two suspects arrested and charged.

They apparently didn’t realize until later it was a policeman they’d killed.

Hill was convicted and sentenced to 100 years in prison.

Now, nearly 65 years old, he’s trying to get out on parole.

As they do with every cop killer, Officer Pollard’s fellow officers are asking the Prisoner Review Board to keep Hill behind bars.