A Canadian teen drowned and spent 38 minutes underwater during a high school swim class before anyone realized that he was at the bottom of the pool, according to reports.

The coroner’s investigation released Monday urged schools to overhaul their swimming instruction programs following the death of 14-year-old Blessing Claude Moukoko last February, the Montreal Gazette reported.

The eighth-grader was partaking in swimming lessons Feb. 15 at Montreal’s Centre Père-Marquette, when he apparently drowned in the deep end of the pool. Classmates spotted his submerged body after the physical education class ended, officials said.

Moukoko was pulled from the water and CPR was performed on the teen before emergency responders rushed him to Maisonneuve-Rosemont Hospital.

But Moukoko had suffered severe brain damage and attempts to revive him were unsuccessful, according to CTV News.

The teen died six days later.

The coroner said in the report that water safety — not instruction — should be the focus of swimming courses.

“It just breaks my heart. It’s hard for me to think about this teacher who was there when it happened. It’s just terrible,” Montreal Mayor Valérie Plante told the Montreal Gazette. “So let’s make sure that our kids know how to behave in water and let’s make sure that school boards have enough resources so they can make sure that everybody’s safe.”