A 17-year-old boy pleaded guilty to drug trafficking Friday during his trial on charges related to the deaths of two teens on the Paul Band First Nation in March 2009.

The youth, who cannot be named under the Youth Criminal Justice Act, entered the surprise pleas during his trial in Stony Plain, Alta.

Leah House, 14, and Trinity Bird, 15, died in hospital days after they ingested the stimulant ecstasy at a March 22, 2009, wedding celebration on the First Nation west of Edmonton.

A third teen was also taken to hospital after ingesting the drug but was later released. A fourth girl was assessed and treated at the scene.

The youth was originally charged with four counts of drug trafficking, but one charge was stayed, because the evidence failed to show that he sold drugs to one of the girls. He also pleaded guilty to failing to comply with an undertaking.

The youth will be back in court for sentencing on Nov. 19.