More than 25 arrested in raids targeting fentanyl-laced heroin

CHICAGO -- A series of Chicago police raids led to the arrests of more than two dozen convicted felons and suspected gang members.

The charge: Selling heroin spiked with the painkiller fentanyl. In combination, the two drugs are highly concentrated and potentially lethal.

Undercover officers arranged drug buys and then, the evidence they collected allowed police to target at least 25 people.

The roundup has been going on since Thursday morning.

Dozens of people have died of fentanyl-related overdoses over the past year and a half in Cook County, according to The Chicago Tribune.

Chicago Police Superintendent Eddie Johnson will update the media this afternoon on the progress of the major drug sweep.