About this series

Times staff writer Sam Quinones is the author of two books about Mexico, where he lived for 10 years. For this series, he traveled to Colorado, Idaho, Ohio, West Virginia and Xalisco, Mexico, to track the spread of black-tar heroin. He interviewed police narcotics officers, federal drug agents, prosecutors, public health officials, addiction experts and imprisoned former dealers and addicts across the U.S.

Part 1: Pushing heroin into the heartland

Part 2: Black tar packs a deadly punch

Part 3: Drug money transforms a backwater