A teen collapsed and died during a game of basketball during an overnight sleepover at Marist High School in Chicago.
Paul Simmons Jr., 17, was attending a senior "lock-in" at the high school and playing basketball in the school's gym.
"He was very special," said his father Paul Simmons, Sr. "He left too soon."
A Friday autopsy indicated the teen died of hypertrophic cardiomyopathy, a thickening of the muscle of the heart. It is one of the leading causes of sudden cardiac death in young athletes.
Simmons, Jr. was with more than 260 classmates Thursday at an all-night "senior lockdown" when he suddenly slumped to the floor during a game of basketball. He was pronounced dead at Advocate Christ Medical Center in Oak Lawn shortly after midnight.
As he greeted well-wishers on the steps of his South side home, Simmons Sr. was remembering a son who was polite, helpful and well-liked by everyone he knew.
Though seniors didn't have class Friday, grief counselors were on hand for students who needed them. At school, Simmons was being remembered as much for his talents in the classroom as on the court.
"He was a cornerstone of the senior class," said principal Larry Tucker.