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CHICAGO -- More than 65 gang members were charged Thursday in a major sweep targeting fentanyl-laced heroin and cocaine.

Chicago police teamed up with the feds in the sting they called "Operation Sweet Dreams" targeting drug dealers on the West Side.

The arrests come a month after police shut down a drug ring on the South Side.

“This takedown, which is large and significant, is the culmination of a 14-month joint state and federal investigation,” said U.S. Attorney Zachary Fardon.

According to the criminal complaint, prosecutors say Operation Sweet Dreams brought in 3.8 Kilograms of heroin, much of it laced with fentanyl, 3 kilos of cocaine, nearly $400,000 and over a dozen guns.

It started with a rash of drug overdoses going back to the fall of 2015, over 70 of them were in a three day period.

That got law enforcement’s attention and undercover officers began making small buys in a stretch of the West Side along the Eisenhower Expressway. On the strength of those buys, they got wiretaps and kept on working.

Fentanyl is a synthetic and is 40 to 50 times more potent than heroin. Dealers will cut their stashes with it to make a cheaper, stronger product. It’s that strength that kills as they often go too far.

“Heroin and fentanyl are killing people on a daily basis in the greater Chicago area,” Fardon said.

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