CHICAGO — Federal prosecutors have charged 12 people who allegedly trafficked fentanyl-laced drugs on the South Side of Chicago.

The charges were announced Wednesday and came after what the U.S. Attorney’s Office called a multi-year investigation led by the FBI, which included controlled narcotics purchases, surveillance and wiretapping.

Law enforcement agents seized nearly $400,000 in alleged cash proceeds, cocaine, heroin, marijuana, Bentley and Mercedes-Benz cars and a custom-built motorcycle during the investigation.

According to a news release, some of the people charged allegedly sold or tried to sell drugs in other states, including Wisconsin, Minnesota and Ohio.

Personnel with the FBI Chicago Field Office, Chicago Police Department, Cook County State’s Attorney’s Office, Rock County, Wisconsin Sheriff’s Office and Indiana State Police assisted with the investigation.