Amreil Watson was set to turn 16 on Sunday, the sophomore at Cesar Chavez High School was a standout basketball player.
His friends and teammates say he died doing what he loved.
"At first I didn't believe it until the fire truck was there, and I was like that is weird because I was just talking to him, and it was just unexpected," said Mikael Richardson.
Watson was playing a pickup basketball game Monday around 3:30 in the school's gym when he collapsed.
"All of a sudden he kind of had a false step and went down, and tried to get up and scramble to go and get back on defense and he couldn't get himself up," said coach Gary Lee.
Lee performed CPR until paramedics arrived. He said the 16-year-old at 6'4" with good grades, and beloved by his teammates, had a bright future.
"They are somber, they are heartbroken, their eyes are red, their heads are down, but as a group they pick each other up and keep each other going," said Lee.
"It's rough, but the kids here are special to me, so I have got to be there for him," he said.
During the recent playoffs Watson, who was number 24, suited up and played for the varsity team.
"When he was down he was the type of person who would keep a smile on your face, and cheer you up. He was just a chill person and everybody loved him," said Richardson.