Two teens found dead outside a North Carolina elementary school last month died of carbon monoxide poisoning, multiple news outlets report, citing an autopsy report.

Britany Carolina Munoz Ramirez, 17, and Ailton Sebastian Tirado-Martinez, 16, were discovered dead in a car parked outside Don Steed Elementary School on Oct. 24, McClatchy News previously reported. Both were juniors at Hoke County High School in Raeford, school district leaders confirmed.

“Dealing with this tragedy is going to take time, and we will be here for every student, every family, and every staff member and will continue to provide the support needed,” Hoke Couty Schools Superintendent Debra Dowless said in a statement at the time.

The autopsy, released last week, showed neither Ramirez or Tirado-Martinez had underlying health conditions or a history of drug abuse, WNCN reported. The teens had attended a friend’s party earlier that evening and were heading home.

McClatchy News reached out to the state’s Office of the Chief Medical Examiner on Friday, Nov. 19, and is awaiting a response.

The sheriff’s office previously said the teen’s deaths appeared accidental and that they didn’t believe foul play was involved.

A memorial service was held for both teens on Oct. 30, according to obituaries posted online.

Raeford is about 90 miles southwest of Raleigh.