A Philadelphia woman was found dead at the Firefly Music Festival in Dover, Delaware, Pitchfork reports. The 20-year-old woman, identified as Caroline Friedman, was discovered unconscious by officers in Firefly Camping Lot 18 at approximately 6:30 a.m. Sunday morning.

Friedman was then transferred to Bayhealth Kent General Hospital around 6:55 a.m., where she was pronounced dead. The cause of death is currently under investigation, but police do not suspect foul play. According to Philly.com, the Sunday morning death is the first in the festival’s seven-year history. Last year, however, human remains were discovered close to the Firefly campgrounds during the festival.

The 2018 Firefly Music Festival began Thursday, June 14, and concluded Sunday, June 17. The annual event hosted a slew of artists including Eminem, The Killers, Kendrick Lamar, Arctic Monkeys and many more. Firefly attracts large crowds, and in 2017, organizers said 90,000 were in attendance.

Deaths during music festivals are not unusual. More than a dozen people have died at the Bonnaroo Music and Arts Festival in Manchester, TN, including the recent death of a 35-year old man on June 8. DanceSafe, a non-profit designed to increase safety in the EDM community, warned drugs sold as MDMA (Molly) are often sold fraudulently. The group confirmed out of more than 500 samples of drugs sold as Molly, only 60 percent of the samples contained MDMA.

Firefly issued a statement concerning the recent death of Caroline Friedman, saying, “We express our deepest condolences and sympathy to the family and friends of Ms. Friedman. We are fully cooperating with the Dover Police Department with their investigation of this”