As a Chicago police officer, Shannon Spalding worked undercover in some of the toughest parts of the city -- only to discover some of the most dangerous criminals were fellow police officers. She risked her life to stop them. Soon after joining the Chicago Police Department in 1996, Spalding drew an assignment in one of the most violent neighborhoods in the city. To survive, Spalding leaned on veteran cops like Ronald Watts. In 2006, a decade after Spalding was trained by Watts, she had a new assignment in the narcotics division. "I was the undercover. I would go out, I would make the controlled narcotics purchases," Spalding explained. Her partner, Danny Echeverria, would swoop in and make arrests. But during police interviews, something strange started happening. "People would say 'I can't believe you're going to arrest me when one of your own is actually running the narcotics trade,'" said Spalding. [She] learned Watts and his crew would plant drugs on residents of the Ida B. Wells projects and extort cash. Spalding and her partner would eventually learn Watts' bad deeds had been going on for years. [They] would spend years undercover investigating Ronald Watts and his team. In February 2012, Sgt. Ronald Watts and one of his officers, Kallat Mohammed, were arrested after being caught robbing a drug courier of $5,200. That courier was Spalding's informant and was wearing an FBI wire. Both Watts and Mohammed were convicted. Watts was sentenced to 22 months and Mohammed received an 18-month sentence. Aided by that investigation, more than 60 people wrongfully arrested by Watts and his team have now been exonerated.