A Harker Heights teenager who passed away Thursday after a morning run has been identified as 19-year-old Nicholas Tyler Thomas.

KWTX reports that Thomas participated in an organized group run Thursday morning. Thomas later passed out and stopped breathing while riding with a family member around 9:30 AM.

Efforts to resuscitate Thomas proved unsuccessful, and he was pronounced dead at Seton Medical Center in Harker Heights.

Thomas' remains were scheduled to undergo an autopsy as investigators work to determine what caused his death.