VANCOUVER - A British Columbia man who plied two teenage girls with drugs and alcohol and failed to intervene as they died has been declared a dangerous offender.

Martin Tremblay of Richmond has been handed an indeterminate prison sentence.

Friends and family of 17-year-old Martha Jackson and 16-year-old Kayla Lalonde cried and cheered as a B.C. Supreme Court judge handed down his decision.

Tremblay was convicted of criminal negligence causing the girls' deaths in March 2010 for inviting them to his home, giving them drugs and alcohol until they passed out and videotaping himself sexually assaulting them.

The sex offender failed to help the girls when their conditions deteriorated and drove Lalonde to Burnaby, where he left her on the ground.

Jackson stopped breathing at his home the following morning, but Tremblay tried to persuade another person not to call 911.