Chicago police and DEA agents conducted a series of raids on a gang suspected of dealing a deadly heroin-fentanyl mix that has killed more than 130 users, USA Today reported June 22.

Raids conducted in Chicago, Texas and Ohio resulted in 30 arrests, including a Chicago police officer with alleged gang ties. The raids were the result of a yearlong investigation into the Mickey Cobras, a gang suspected of dealing the heroin/fentanyl mix and other drugs in at least 10 Chicago locations. The mix is blamed for 53 deaths and 362 other overdoses in Chicago alone.

Court papers allege that Chicago Mickey Cobras members got the heroin/fentanyl mix from another gang member in Texas, who in turn got the drugs from suppliers in Mexico.