AMES, Iowa (AP) – The increasing presence of a deadly synthetic opioid called “pink” or “U4” has prompted warnings from Iowa authorities. Ames police spokesman Geoff Huff told The Des Moines Register that the drug, also called “pinky,” has been identified in a handful of Ames cases since June. But he says there are other cases that police don’t know about.

In June a joint statement from four state health and public safety agencies warned the public about U4 as a response to a nonfatal overdose in eastern Iowa. In November the U.S. Drug Enforcement Administration categorized U4 among drugs with the highest potential for abuse or addiction, comparable to methamphetamine, cocaine and heroin.

Huff says his department is warning parents that U4 poses great risks to high school and college students.