"Definitive causes of death have not yet been determined, however, both appear to have involved the drug MDMA (ecstasy, or molly)," read a statement from New York City officials. "The Electric Zoo organizers have worked with City officials to reduce health risks at this event, but in view of these occurrences, the safest course is to cancel the remaining day of the event."

The victims were identified as Jeffrey Russ, 24, of Rochester, N.Y., and Olivia Rotondo, 20, of Providence, R.I. Founders of the EDM festival and artists alike expressed their shock and sympathies.

"The founders of Electric Zoo send our deepest condolences to the families of the two people who passed away this weekend. Because there is nothing more important to us than our patrons, we have decided in consultation with the New York City Parks Department that there will be no show today."