The US Drug Enforcement Administration says that less fentanyl is present in the nation’s illicit pill supply and that it’s helping drive overdose deaths down in the United States. But experts say that there are limitations to this claim and that many other factors are probably playing a role.

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

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