Almost two years after the synthetic opioid Pink” killed two 13-year-old boys in Park City, officials are warning that the drug — or something like it — is back.

The Summit County Attorney, Summit County Sheriff’s Office and Park City Police Department issued a warning that “some shipments [of the drug] were intercepted,” but it is “unknown what other substances may have also been received and distributed.” It further cautioned that the drugs “are dangerous and of unknown potency and composition.”

According to Summit County Attorney Margaret H. Olson, the investigation has uncovered more than one shipment this summer, and the case was “just presented to our office for screening."

In a release, authorities said parents are urged to talk to their children about the “deadly substances,” which were “ordered via the ‘dark web’ and mailed into Park City”; to be on alert for suspicious packages sent through the mail or shipping services; to treat any suspicious packages with extreme caution and not touch them; and to contact police immediately.

Authorities said at least one of the teens involved in the current investigation was also involved in the 2016 purchase of Pink, also known as U-47700, that resulted in the deaths of Grant Seaver and Ryan Ainsworth.

Olson said her office will file charges in the 3rd District Juvenile Court.