DENVER (AP) – Colorado’s new U.S. attorney is encouraging law enforcement in the state to investigate opioid overdose deaths as homicides. Jason Dunn is also digging into data on doctors and nurses who prescribe unusually large quantities of opioid painkillers, with an eye toward prosecuting those who are illegally diverting the drugs and, he feels, adding to the scourge of heroin. Dunn says there are dealers who either know they are selling fentanyl instead of heroin or know that it has already caused death and continue to sell it. The tactics mark a redoubling of efforts that began in Colorado’s U.S. Attorney’s Office under Dunn’s predecessors and amid growing efforts statewide to tackle an epidemic that killed 560 Coloradans in 2017.