(Mark Finkenstaedt for The Washington Post)

A 16-year-old high school football player in suburban Pittsburgh who collapsed and died during an early-season football practice on Wednesday had a non-cancerous tumor in his heart, according to WTAE-TV in Pittsburgh.

Noah Cornuet had just finished running sprints during a heat-acclimation practice with the Burrell High School football team on Wednesday evening when he collapsed. He was taken to an area hospital, where he was pronounced dead. On Thursday, an autopsy revealed that the tumor caused Cornuet’s death.

On Thursday, parents and students gathered at Burrell High for a candlelight vigil. Noah’s parents were there and addressed the crowd.

“He was such a good boy. He never hurt anyone and never would have. We are so proud of the child and young man he grew up to be, and we’re just mourning the loss of the life he would have had, because all we really wanted was for him to grow up and be a successful member of society,” Pam Cornuet said, per WTAE.

In Pennsylvania, high school football teams are required to go through three consecutive days of non-contact heat-acclimation practices to start the season before they can practice in full. Per the Pittsburgh Post-Gazette, players practice in helmets, shoulder pads and shorts over the first two days before they can wear full gear, and the heat-acclimation practices are limited to five hours daily and no more than three hours at a time, with a minimum of two hours between practice sessions.

It was around 77 degrees when Cornuet collapsed on Wednesday. According to the Post-Gazette, he was the first Western Pennsylvania student to die while playing high school football since 1980.