CHICAGO (CBS) — A special prosecutor will investigate a politically charged, fatal fight involving a nephew of retired Mayor Richard M. Daley.

Cook County Judge Michael Toomin issued the ruling Friday after the reopening of the case was  pushed by the family of David Koschman and other critics of the original investigation.

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Early on the morning of April 25, 2004, Koschman reportedly had a confrontation with Daley nephew Richard “R.J.” Vanecko outside a bar in the Rush and Division Street nightclub district. The quarrel allegedly prompted Vanecko to punch or push Koschman, who hit his head on the ground and died 12 days later.

LISTEN: WBBM Newsradio’s Lisa Fielding reports

“I hope I can finally get some justice for David,” Nanci Koschman, the victim’s mother, told reporters.

Investigators initially determined Vanecko punched Koschman in self-defense. But as WBBM Newsradio’s Lisa Fielding reports, Judge Toomin was critical of the way Chicago police and the Cook County State’s attorney handled the investigation.

“The system has failed David Koschman up to this point,” the judge said. “There is an appearance of impropriety.”

“When you have a dead body, someone’s going to jail,” he continued. “Not in this case. This is a fiction of self defense.”

The judge, however, rejected claims that Cook County State’s Attorney Anita Alvarez was too close to Daley, her former boss, to run a fair investigation.

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“I will always follow the evidence and the law wherever it leads, without any influence from anyone,” Alvarez said in reaction to Friday’s decision.

Koschman’s death was ruled a homicide. A series of stories in the Chicago Sun-Times led police to re-examine the case but no one was ever charged.

Detectives reportedly determined Koschman was the aggressor, based on witness accounts. But those witnesses later said they never told police Koschman was the aggressor.

Alvarez’s office also declined to press charges, saying there was not enough evidence to sustain criminal charges against Vanecko. But last year, Alvarez did ask Illinois State Police to examine the Chicago Police investigation.

Koschman’s family’s petition for a special prosecutor noted irregularities in the investigation, including false official reports and a case file that went missing, and says the investigation might have been influenced by Vanecko’s relationship to Mayor Daley. The petition said the irregularities require an independent investigation.

The Better Government Association had filed an amicus brief in the case, and urged Judge Toomin to appoint a special prosecutor.

“The judge delivered a damning verbal indictment of the system from top to bottom,” BGA executive director Andy Shaw said Friday.

Shaw has said the goal is not to go after Vanecko, but to provide solace for the Koschman family.

Vanecko, who was not charged, denies any wrongdoing.

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A special prosecutor could seek charges against him and could pursue sanctions against police or the state’s attorney’s office if it is determined misconduct took place.