The case is believed to be the first criminal prosecution related to a death caused by the synthetic drug protonitazene in the U.S.

Protonitazene, a synthetic opioid three times stronger than fentanyl, was connected to an overdose in Stevenson Ranch. Dealer knew his pills had killed, but kept dealing anyway.

The U.S. Department of Justice's Los Angeles office filed charges in what could be the nation's first death-resulting criminal case involving a synthetic opioid that prosecutors say is "up to three times more powerful than fentanyl.

A Santa Clarita man has been arraigned on an indictment alleging he distributed protonitazene – a novel synthetic opioid that is up to three times more powerful than fentanyl – which resulted in a victim’s fatal overdose this spring,