Over a dozen men convicted on drugs charges in Chicago have been exonerated after claiming they were framed by a police sergeant and his team of officers.

The convictions were vacated two months after lawyers for the 15 men filed a joint petition seeking to overturn 18 criminal drug convictions among them, the Chicago Tribune reported.

The dismissal is believed to be the first-ever mass exoneration in Cook County, according to the report.

“In these cases, we concluded, unfortunately, the police were not being truthful, and we couldn’t have confidence in the integrity of their reports and their testimony, and so, in good conscience, we could not see these convictions stand,” Mark Rotert of the Cook County Conviction Integrity Unit said during a press conference. …