By Megan Crepeau and Jason Meisner

Cook County prosecutors dropped all charges Thursday against 15 men who alleged they were framed by corrupt former Chicago police Sgt. Ronald Watts and his crew.

Ten of the men were in court as Judge LeRoy Martin Jr., presiding judge of the criminal division, threw out the convictions en masse -- believed to the first mass exoneration in county history.

And there could be more ahead. Joshua Tepfer, the lead attorney for the 15 men, said Watts led a crew of cops -- many still on the force -- who made some 1,000 arrests. Authorities still must deal with more than 400 convictions tainted by Watts and his men, he said.

"It needs to be investigated and vetted about how many of those are appropriate to overturn," Tepfer told reporters at the Leighton Criminal Court Building. "We are very much in the process of doing that."

Mark Rotert, head of State's Attorney Kim Foxx's Conviction Integrity Unit, said prosecutors continue to review Watts-related convictions on an individual basis -- what he called "a very exacting process."

"Cases have to be evaluated individually and on their own facts," Rotert said following the dismissal of the charges against the 15 men.

It marks the third consecutive day that prosecutors dropped charges at the county's main criminal courthouse because of alleged police misconduct. Jose Maysonet, 49, walked free Wednesday after 27 years in custody for a double murder when a sergeant and four detectives -- all retired -- indicated they would assert their Fifth Amendment right and refuse to answer questions about the alleged confessions they obtained.

On Tuesday, Arthur Brown, 66, was released after county prosecutors reversed course and dropped murder charges against him, saying "significant evidentiary issues" raised "deep concerns" about the fairness of his conviction. Brown had been in custody 29 years for a double murder.

The mass exoneration Thursday comes two months after lawyers for the 15 men filed a joint petition seeking to overturn a total of 18 criminal drug convictions, alleging that Watts and his crew framed all of them between 2003 and 2008.

Because of the age of the cases, all 15 men had completed their sentences; two remain in custody on unrelated charges.

Watts and an officer under his command were sent to federal prison in 2013 for stealing money from a drug courier who'd been working as an FBI informant.

Tepfer, of the Exoneration Project at the University of Chicago Law School, said Thursday that he was "extraordinarily heartened" by the state's attorney's decision to throw out all the convictions at once.

"This is something that's rarely done in the country, as far as I know, where cases are looked at en masse because of some sort of law enforcement or official problem and in the interest of justice that we have to do a clean sweep," he said.

A state's attorney spokesman said nobody in the prosecutors' office could recall ever dropping so many convictions at one time.

Since last year, the Chicago Tribune has written several front-page stories detailing the scandal over Watts' nearly decadelong run of corruption.

Five people had previously seen their Watts-related convictions thrown out, so Thursday's move brought the total to 20. In addition, two Chicago police officers who alleged they were blackballed for trying to expose Watts' corruption years ago won a $2 million settlement in their whistleblower lawsuit.

Watts has repeatedly been accused of forcing residents and drug dealers alike to pay a "protection" tax and putting bogus cases on those who refused to do so. In case after case, when Watts' targets complained -- to the Police Department or in court -- judges, prosecutors and internal affairs investigators all believed the testimony of Watts and other officers over their accusers, records show. In addition to the alleged frame-ups by Watts, the petition filed in September highlighted a broken system of police discipline that allegedly protects bad officers and punishes those who tried to expose his corruption.

Despite mounting allegations, Watts continued to operate for years amid a lengthy police internal affairs division probe as well as investigations by the state's attorney's office and the FBI, according to court records. When Watts was finally caught, it was on relatively minor federal charges, and he was given a break at sentencing by a federal judge who talked tough but in the end handed him only 22 months in prison.

Meanwhile, at least seven other officers who were part of Watts' team are still on the force, including one who has since been promoted to sergeant and another who was found by a jury this year to have shot a teen in the back without justification.

Among the petitioners whose case was overturned Thursday was Leonard Gipson, who filed a complaint with the Chicago Police Department in 2003 alleging the sergeant had framed him on a drug charge because he'd refused to pay "protection" money.

Gipson's complaint went nowhere. Four months later, with his drug case pending, Gipson was visiting his girlfriend in the Ida B. Wells public housing complex when he again ran into Watts, who had been notified of the complaint against him.

"Let me see if you can bond off on this," Watts said to Gipson before handcuffing and planting 28 grams of heroin on him, Gipson alleged in the petition. After two years in jail awaiting trial, he pleaded guilty on the advice of his attorney, who noted it was his word against the police's.

On Thursday, Gipson was among those in court to witness history.

"Watts always told me, 'If you're not going to pay me, I'm going to get you,'" Gipson told reporters. "And every time I ran into him, he'd put drugs on me. Every time."

Gipson, 36, said he feels like "a brand new baby" now that his record has been cleared.

Another alleged victim, Taurus Smith, was 17 years old at the time he claimed Watts had him falsely arrested on a narcotics charge. Shortly after he bonded out, Smith's mother took him to file a complaint with the now-defunct Office of Professional Standards.

The next day, Watts and two other officers confronted Smith outside a building at Ida B. Wells, where Watts made it clear that he knew the teen had dared complain, according to Smith's sworn statement in the petition.

"Watts had his service weapon on his waist and another gun in his hand," Smith said in the statement. "He said to me, 'This is grown-man s---.' ... He then threatened he would plant the gun on me if I didn't leave it alone."

Smith said he again reported the incident to his mother, who told him they were going to have to move. Weeks later, they packed up and left the Ida B. Wells complex, he said.

Gipson said in his sworn statement that everyone in the neighborhood knew of Watts' reputation as a crooked cop. Watts had warned him that if he didn't pay his street tax, Gipson said, "I would go to jail every time he ran into me." Gipson tried to fight his drug charges in court, but after a Cook County judge sided with the officers and denied his motion to suppress evidence, he had little option but to cut a deal. He pleaded guilty to both counts in exchange for four months in boot camp.

But it wasn't over for Gipson. In August 2007, two years after his release from custody, he was leaving his girlfriend's house in Ida B. Wells when Watts spotted him and asked, "Do you have something for me?" according to Gipson's affidavit.

Gipson left the building, but when he came back a short time later, Watts and several members of his team surrounded him, he said. Watts took a bag of drugs out of his pocket and said, "These are your drugs, hard-ass," then handcuffed Gipson and took him to the station, according to Gipson's statement.

Court records show Gipson pleaded guilty to heroin possession and received four years in prison. His only criminal convictions are the three cases involving Watts, according to records.

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