SANTA ROSA, Calif. (AP) - Authorities say a 14-year-old Northern California girl who died during a sleepover last summer overdosed on a chemical found in so-called "date rape" drugs, but it's unclear how she got the drug.

Sonoma County Sheriff's Lt. Dennis O'Leary says Tuesday that Takeimi Rao died in July from drinking a fatal dose of Gamma-Hydroxybutyric or GHB.

Investigators are still trying to determine whether the Santa Rosa teen ingested the drug intentionally or accidentally. GHB is found in some industrial cleaning solvents.

Authorities initially believed the teenager may have died of alcohol poisoning or choked on her vomit after drinking vodka with three friends.

The test results were released almost seven months after Rao was found dead in her bedroom. She had recently graduated from Rincon Valley Middle School in Santa Rosa.