CHICAGO (CBS/AP) — Near the end of his third trial for the 1982 murder of a Chicago police officer, special prosecutors on Thursday dropped all charges against Jackie Wilson, just after a current Cook County state’s attorney revealed he was a long-time friend with a key witness in the case.

The decision means Wilson, now 60, cannot be tried a fourth time for the killing of Chicago Police Officer Richard O’Brien. Another officer, William Fahey, was also killed, but Wilson was acquitted of murder in Wilson’s death at his second trial in 1989.

READ MORE: Man Shot And Killed In Dispute Outside West Chatham Home

Special prosecutors handling the case against Wilson announced the decision to drop the charges just after Cook County assistant state’s attorney, Nicholas Trutenko testified during the defense case that he was a long-time friend with William Coleman, a central witness in Wilson’s 1989 trial.

Wilson’s defense team has portrayed Coleman as an “an international con man who repeatedly perjured himself decades ago to secure Wilson’s conviction,” but neither prosecutors nor defense attorneys in the case knew whether Coleman was alive or dead.

Trutenko testified he had been in touch with Coleman as recently as this week, noting he became godfather to one of Coleman’s daughters several years ago.

When pressed as to whether he had ever disclosed that friendship to the prosecutors’ office, Trutenko said he did not believe he had any obligation to do so.

“If proven, the failure of Trutenko to reveal the existence of a key witness – and his relationship with that witness – is serious professional misconduct that was never disclosed to Jackie Wilson during his decades of wrongful incarceration,” Wilson’s defense attorneys said in a press release after charges were dropped.

Wilson, 59, was being tried again despite successfully arguing in prior hearings that he was tortured into confessing to taking part in the killings by notorious former Chicago Police Cmdr. Jon Burge. Wilson has claimed Burge and detectives under his command beat him with a dictionary, stuck a gun in his mouth and played Russian roulette, and gave him electric shocks.

Wilson’s 1989 conviction was thrown out in 2018 by Judge William Hooks after allegations that Wilson had been tortured by Burge, who is now deceased, into confessing to a role in the shooting. Hooks was hearing evidence in Wilson’s third trial. Wilson has been free on bail since Hooks threw out his conviction in 2018.

READ MORE: City Was Warned About Thousands of Corroding Light Poles But Failed to Fix Many, CBS 2 Investigation Finds

Defense attorney Flint Taylor said his team was pleased Thursday night that the case was dismissed by the special prosecutor.

“It should have been dismissed and never gone to trial. But it did and it was a colossal waste of taxpayers’ money,” Taylor said.

Wilson’s first conviction was overturned by an appellate court. At a retrial in 1989, he was acquitted of Fahey’s murder but convicted of O’Brien’s.

His brother, Andrew Wilson, was convicted of firing the shots that killed both officers, and is serving a life sentence.  At question in Jackie Wilson’s third trial was whether he also participated in the murders, or was legally responsible because prosecutors say the two brothers were plotting to break a friend out of police custody while the friend was in the hospital.

Burge has never faced criminal charges for abuse. He was fired from the police department in 1993 over the 1982 beating and burning of Andrew Wilson.

Wilson died in prison in 2007, convicted twice in the murders of O’Brien and Fahey.

Burge died in 2018, four years after he was released from prison, having been tried and convicted of lying about the torture of suspects in police custody.

This story has been updated to correct the details on Jon Burge’s death and Wilson’s death.

MORE NEWS: Chicago Weather: Rain Arrives Sunday

(© Copyright 2020 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)

CBS 2 Chicago Staff