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HOUSTON (NewsNation Now) — The Houston police chief said authorities are investigating reports of possible druggings at a Houston music festival that left eight people dead and hundreds more injured.

Houston Police Chief Troy Finner said a security guard told police that he felt a prick in his neck during the chaos at the Travis Scott concert and lost consciousness while being examined by first responders. He was revived by the opioid antidote Narcan.

“The medical staff did notice a prick that was similar to a prick that you would get if somebody was trying to inject,” Finner said.

Finner said his department noticed attendees “going down” during the concert at 9:30 p.m. and immediately notified concert organizers. The event was called off 40 minutes later after discussions that included the fire department and officials with NRG Park.

Part of the investigation will include reviewing how the area around the stage was designed, the fire chief said.

The dead, according to friends and family members, included a 14-year-old high school student, a 16-year-old girl who loved dancing and a 21-year-old engineering student at the University of Dayton. The youngest was 14, the oldest 27.

Authorities did not disclose the causes of death, and the dead were not immediately identified.

Scott, one of music’s biggest young stars, founded the Astroworld Festival in 2018. The 30-year-old Houston native has been nominated for eight Grammy Awards. He has a 3-year-old daughter with Kylie Jenner, who announced in September that she’s pregnant with their second child.

The Associated Press contributed to this report.