(CENTRALIA, IL) — Two more arrests have been made in the eight-month investigation into the trafficking of heroin and methamphetamine in the community. Both 38-year-old Mark McClain, of Chicago, and 26-year-old Dustin Marshall, of Salem, are in the Marion County Jail on charges stemming from the investigation that has so far resulted in the arrests of more than a dozen other people. McClain was arrested in Chicago on a Marion County warrant charging him with six counts unlawful delivery of a controlled substance. He was transported to the Marion County Jail Wednesday with bail set at $75,000. Marion County Sheriff’s deputies arrested Marshall on Wednesday. He’s charged with three counts unlawful delivery of a controlled substance and his bail is set at $30,000. The first round of warrants was served June 2, with 10 people being arrested in Centralia and one in Salem. Since that time four others have turned themselves in to authorities and two others have been arrested in connection with the investigation that was a joint operation between the Centralia Police Department and Marion County Sheriff’s Office.