Sources tell FOX 32 that several Chicago Police officers part of a tactical gang unit are being investigated by the FBI.
The group includes a police sergeant with more than two decades on the force.
Sources said the FBI is looking into accusations that the they stole money from drug dealers.
None of these officers are in federal custody and no charges have been filed against them.
Sources close to the investigation said Wednesday this is part of a several-month long investigation that included wire-tapping the officers' cell phones and some of the sting operations were caught on camera.
Armed with a search warrant – FBI agents raided at least one of the officer's homes, where they found marked bills as part of the undercover probe.
A spokesperson for the Chicago Police Department released this statement, “Integrity and accountability are paramount to the Chicago Police Department and we work hard everyday to build and safeguard public trust. To that end, we cannot comment on any investigation - internal or otherwise - until or unless criminal charges are filed."
The FBI and the Fraternal Order of police declined to comment Wednesday night.