A 22-year-old man who attended the Beyond Wonderland rave in San Bernardino County died after collapsing at the event, authorities said.
John Hoang Dinh Vo of San Diego went into cardiac arrest after suffering a possible seizure at the event, held at the San Manuel Amphitheater in Devore, a venue owned by San Bernardino County.
Vo was transferred to Loma Linda University Medical Center and pronounced dead after 11 p.m. March 20, said Randy Emon, supervising deputy coroner.
The cause of death has not been determined, pending toxicology tests to detect the presence of any drugs in his body.
Jennifer Forkish, a spokeswoman for Insomniac Inc., the company that produced Beyond Wonderland, said in a statement: "We received the heartbreaking news that a guest of the festival passed away after attending the show.
"While the cause of his passing will take time to determine, what we do know is that somewhere his family and friends are grieving," she continued. "To them, we extend our thoughts and prayers during this difficult time."
Three people have died in circumstances involving Ecstasy among people who attended San Bernardino County raves staged by Insomniac since 2006, according to a Los Angeles Times review of coroner records.
The most recent occurred in September 2013. Arrel Christopher Cochon, a Los Angeles City College student who lived in East Hollywood, died of an Ecstasy and methamphetamine overdose after collapsing and suffering a seizure at Insomniac's Nocturnal Wonderland concert in Devore.
The Times examined coroners' records in nine states after the top executives of Insomniac and Go Ventures -- Pasquale Rotella and Reza Gerami, respectively -- were indicted on bribery and other charges in connection with raves held at the Los Angeles Memorial Coliseum and Sports Arena.
They are accused of making side payments to a Coliseum manager to help them win government approval of the raves and to keep their costs down.
Both promoters have pleaded not guilty and are awaiting trial. The case grew out of Times reports on financial ties between the two men and the Coliseum events manager, Todd DeStefano, who was also indicted and has pleaded not guilty. They came under scrutiny after a 15-year-old who attended a 2010 Insomniac rave at the stadium died of an Ecstasy overdose.