COLUMBIA, S.C. (CBS/AP) — A coroner says a 16-year-old South Carolina high school student who collapsed and died in a classroom had heart problems caused by drinking too much caffeine.

Richland County Coroner Gary Watts said at a news conference Monday that Davis Cripe drank a large Mountain Dew, a latte from McDonald’s and an energy drink in the two hours before his heart fell out of rhythm at Spring Hill High School near Chapin on April 26.

All that caffeine led to a cardiac event that killed Cripe. “We lost Davis from a totally legal substance,” Watts said.

Watts says the boy was a model student.

“[Cripe] was totally against drugs, he was totally against alcohol,” Watts added. “He didn’t do any of that.”

Watts says like many, Cripe was doing something he thought was totally harmless, but Watts said the drinks can be very dangerous.

“This is what’s dangerous about this,” Watts said. “You can have five people line up and all of them do the exact same thing with him that day, drink more, and it may not have any type of effect on them at all. It’s not something that just because you drink one drink or three drinks is necessarily going to have this effect on.”

The boy’s parents were also at the announcement.

“Davis was a great kid, and being his parent was a great honor to Heidi [his mother] and me,” said Sean Cripe, his father.

He echoed Watts’ call for people to avoid highly caffeinated drinks.

“I stand before you as a brokenhearted father and hope that something good can come from this,” Cripe said. “Parents, please, talk to your kids about the dangers of these energy drinks. And teenagers and students, please stop buying them. There’s no reason to consume them they can be very dangerous.”

An initial autopsy done on the boy could not reveal the cause of death. Further tests were needed to reach the conclusion announced Monday.

(© Copyright 2017 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)