A special prosecutor's probe into allegations of police torture under former Chicago police Cmdr. Jon Burge was a sham, several activist groups said at a rally outside City Hall on Tuesday.

Dozens gathered to demand that Mayor Richard M. Daley reopen the investigation and award new trials to torture victims still incarcerated.

"Mayor Daley, you can't hide! Torture victims need new trials!" the crowd shouted in unison before moving on to chant, "No justice! No peace! No racist police!"

Earlier that day, the group released a report criticizing the four-year, $6.5 million probe into allegations of torture against blacks by South Side detective units in the 1970s and '80s.

The investigation concluded last year that instances of abuse did occur, including beatings and electric shocks, but said criminal charges could not be pursued against the officers involved because the statute of limitations had run out.

The report released Tuesday alleged that the investigation failed to indict crooked cops and watered-down mistakes made by top officials - including Daley, the state's attorney at the time and his former assistant and successor, Richard A. Devine.

The report claims that Daley, Devine and other top officials participated in a "conspiracy of silence" by failing to investigate allegations of torture when they first arose.

At the rally, activists asked Daley to take responsibility for his role in the police torture and to settle civil suits brought forth by exonerated victims.

"[Daley] is definitely wrong and it's time he step up and do the right thing," said Darby Tillis, the first man on death row to be exonerated in Illinois. "He needs to bring these men to justice."

Tillis was exonerated on Jan. 21, 1987 after what he recalled as "nine years, one month and 17 days" behind bars for a crime he did not commit.

Attorney Frank Avila, who is representing torture victim Aaron Patterson, said Daley needs to address allegations of torture and pay retribution to the victims.

His client, Patterson, was exonerated in 2003 and has joined three other victims in a lawsuit against the city. Patterson claims he was beaten, suffocated, deprived of light and food, and threatened with a gun to his head until he falsely confessed.

In total, 148 black men accused Burge and his officers of torture. Many claimed they were beaten, suffocated by a plastic typewriter cover, shocked with cattle prods, handcuffed to a burning-hot radiator, and received electric shocks to the genitals, lips and ears using a black box device.

Burge was fired in 1993 after the city lost a civil suit to convicted murderer Andrew Wilson, who suffered serious injuries as a result of police torture. Burge is now partially retired in Florida and continues to deny any wrongdoing.