The West Metro Drug Task Force began its investigation in early July and says the group distributed at least a half-pound of heroin on a weekly basis.
Julio Cesar Gandara-Quinones, 34; Gustavo Adolfo Valdivia-Garcia, 26; Reynaldo Anguiano-Valdivia, 37; and Acela Davalos-Castanedo, 53, were booked into the Jefferson County Jail.
Investigators say customers would call a central number and a drug runner would meet the customers at various locations.
Investigators seized seven ounces of heroin, worth $36,000 on the street, and $7,000 in currency and vehicles at two different Denver locations, 7600 Tejon Street and 2030 West 26th Avenue.
Investigators are still looking for more leads in the case.
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