Police in northwestern B.C. are hoping an autopsy today will shed some light on how a teenager died in a bizarre incident at a birthday party this weekend.

The 15-year-old boy was attending a supervised party for a 16-year-old girl in Terrace on Sunday night when he collapsed around 1 a.m.

Cpl. Dan Moskaluk said two 15-year-old boys were involved in a physical exchange that ended with one youth being struck at least once in the chest.

An adult supervising the party called 911 when he noticed the teen "did not appear well."

Paramedics performed CPR on the boy while he was transported to Terrace Hospital but he could not be revived. He died at the facility around an hour later.

Moskaluk said the boys were friends and investigators are trying to determine whether the incident was just consensual roughhousing or something considered criminal.

Police are still examining whether alcohol was involved.

The name of the teen is not being released.