A stimulant called Benzo Fury is being blamed for the death of one attendee and the hospitalization of two others at Scotland’s RockNess Festival over the weekend. Those incidents, combined with a bus accident that ended in two deaths on Friday (June 8), marred a weekend featuring performances from Mumford and Sons and Deadmau5.

According to the Daily Mail, the festivalgoer who may have died of an overdose was 19-year-old Alex Heriot. “We are still talking to the police liaison people and we are not sure of the full circumstances of what has happened,” the teenager’s father said. “We are still struggling to take it in.”

The potential drug fatality occurred despite increased efforts by police and the festival’s organizers to keep illegal substances off the grounds. As Rolling Stone reports, this year’s RockNess included drug-sniffing dogs, searches and “amnesty bins” where concertgoers could dispose of contraband without fear of persecution. The head officer told reporters, “If anyone has the tablets described or any other drug — whether controlled or a ‘legal high’ — in their possession, they are advised not to take them and to hand these in.”

Added festival organizer Jim King, “What should be very clear from this information is that legal high does not mean safe, and customers should not go anywhere near these dangerous substances. Festivalgoers should heed the advice given to them by the health professionals and the police, and stay safe by avoiding drugs of any kind.”

RockNess 2012, which marked the sixth year of the Scottish festival, also boasted appearances by Ed Sheeran, Chic, Noah and the Whale, and the Drums.