Two teenagers were found dead at a Tennessee high school and a third was hospitalized hours before graduation possibly due to a drug overdose, the Fayette County Sheriff’s Office said.

The deaths at Fayette Ware Comprehensive High School in Somerville on Tuesday were being investigated, the Sheriff’s Office said in a statement. A third juvenile was taken to a hospital in critical condition, but was later upgraded to stable.

All three of the students attended Fayette Ware Comprehensive High School, the school said in a statement. Their names were not released.

The students were found in the parking lot of the high school, hours before its graduation ceremony was set to begin in the school’s gym, news outlets reported.