BRADFORD, Ont. - Police say the cause of death of a 13-year-old boy who died after swimming in the family pool in Bradford, Ont., remains under investigation.

Police say he had been swimming under water for an extended period of time just prior to surfacing in some sort of distress.

The boy's parents were on the pool deck and his younger brother was in the pool at the time.

CPR was performed by a family member and one of the officers called to the home last night.

Paramedics transported the boy to South Lake Regional Hospital in Newmarket, Ont., where he died.