A 15-year-old girl died and another was hospitalized after authorities said the two were found overdosing on what they believe to be fentanyl-laced pills at a Hollywood high school.

The Los Angeles Police Department said they were alerted of a possible overdose around 9 p.m. Tuesday at Bernstein High School, less than two miles southeast of the Hollywood Walk of Fame.

Lt. John Radtke with the LAPD West Bureau Homicide Unit told reporters a parent became concerned after their teen didn’t come home from school. The stepfather of the teen searched for the teen and wound up at the school. 

Radtke said the stepfather found the teen on the campus “very ill.” The teen said she had a friend in the restroom, so the stepfather alerted a school employee to investigate the restroom, where the two found teen’s friend unresponsive. 

“They rendered aid, called 911. Unfortunately, that victim was pronounced dead here at the scene,” Radtke said. 

The surviving teen was taken to a local hospital. Authorities are withholding the identities of the teens, but they are believed to be students at the school.

Authorities said investigators believe the two victims purchased what the teens believed to be Percocet pills from at Lexington Park, less than half a mile from the school, on Tuesday before immediately feeling ill. The police department said they had two additional calls of overdosed local high school students in the area of the park.

“Our concern is that someone out here is selling pills that may be laced with fentanyl,” Radtke said. 

Fentanyl is a synthetic opioid estimated to be 50-100 times stronger than morphine, according to the U.S. Drug Enforcement Administration. Illicit versions of fentanyl have increasingly been mixed with other street drugs, leading to it be responsible for the most overdose deaths in the county. Overdose deaths from fentanyl climbed to 71,238 last year.