22-year-old SF man among 3 who died during So-Cal music festival

Photo from San Bernardino Co. Sheriff's Dept. Capt. Horace Boatwright's Twitter feed. 

A San Francisco man died early Sunday morning while attending a popular music festival in Southern California, according to the San Bernardino County Sheriff's Department. 

Derek Lee, 22, died around 12:10 a.m. after being taken to Arrowhead Regional Medical Center in Colton, sheriff's officials said.

Lee had reportedly attended the HARD Summer Music Festival, which had taken place Saturday and Sunday at the Auto Club Speedway in Fontana.

Two other attendees, a 22-year-old Chino Hills woman and a 21-year-old San Diego woman, also died over the weekend after being taken to the hospital, according to sheriff's officials.'

The three deaths are not related, sheriff's officials said.

A cause for Lee's death has not been released and is under investigation, sheriff's officials said.

According to a Southern California Fox affiliate, about 146,000 people attended the two-day music festival.