The Fresno High School student who died after collapsing during a physical education class Monday has been identified.

The Fresno County Sheriff’s Office identified the student as Daniel Padilla Jr. of Fresno, a 14-year-old boy.

Fresno Unified School District confirmed Padilla passed out during P.E. before being transported to a hospital, where he later died.

The details of what exactly happened are currently unclear.

“Our hearts are with the student’s family, friends and the entire school community during this incredibly difficult time,” the district said.