Based on available data — as well as interviews with more than a dozen counterdrug officials, drug policy experts and academics — the deadly synthetic opioid fentanyl has displaced heroin as the leading driver of the ongoing opioid crisis in the United States and is contributing to a deadly scramble for market-control back in Mexico. In the second of this three-part series (read chapters one and three), InSight Crime explores these seismic shifts in the regional drug market.
