A 14-year-old girl who was the top seller of Girl Scout cookies in San Diego died suddenly at a school dance, reports ABC News. Sabrina Keller, who sold 3,463 boxes of cookies this year, collapsed at the event held to celebrate the end of eighth grade on Thursday. She was flown to a nearby hospital, but was pronounced dead one hour later. An autopsy was inconclusive, and further tests could take up to 90 days for results. "It's really tragic," said the school principal. "She was a good kid." (More Girl Scout cookies stories.)