A 24-year-old San Francisco man who died while attending the Electric Daisy Carnival rave in Las Vegas had ingested a fatal dose of the drug Ecstasy, authorities said.

The cause of death for Nicholas Austin Tom, a UC Irvine graduate, was MDMA intoxication, the shortened version of Ecstasy’s scientific name, according to the Clark County coroner’s office. Tom was declared dead June 21 at 3:25 a.m. at the Las Vegas Motor Speedway, where the rave was being held.

Tom, who went to Galileo Academy of Science & Technology in San Francisco, returned to the city after graduating from UC Irvine in 2013 with a degree in biological sciences and a minor in psychology and became a medical assistant at UC San Francisco Medical Center.

Grief-stricken family members and friends paid tribute to Tom in online memorial posts, with many remembering him as an inspirational coach of dragonboat teams – a sport involving a large number of paddlers racing on a boat decorated like a dragon. Photos were posted of Tom grinning on the beach, spraying a friend with a water gun, and posing for photos with his arms wrapped around his friends’ shoulders.

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