Convicted sex offender Martin Tremblay was formally charged in relation to the deaths of teenagers Kayla Lalonde and Martha Jackson in a Vancouver court on Thursday.
Tremblay, 45 has been charged with two counts of criminal negligence causing death, two counts of failing to provide the necessities of life and two counts of obstruction of justice.
Lalonde, 16 was found dead on a Burnaby street on March 2, 2010 after witnesses said she had been dumped from a van.
Jackson, 17 died hours later after being rushed by ambulance from Tremblay's Richmond home, where the girls had been partying.
Toxicology results indicated that the apparent cause of death for both girls was a lethal combination of alcohol and drugs.
The ensuing investigation into the friends' deaths involved up to 100 police officers and close cooperation between the RCMP and Vancouver Police Department.
Tremblay was previously convicted of five counts of sexual assault in 2002 and sentenced to 14 months. He was found guilty of giving drugs and alcohol to five aboriginal teenage girls and then videotaping his sex acts with them after they passed out.
In February 2010, Vancouver police took the extraordinary step of issuing a public plea for victims of Tremblay, after a protest on the Downtown Eastside by First Nations women who were concerned about Tremblay's upcoming release from custody.
In September of this year, police announced he was facing seven new charges for sexual assaults on young vulnerable women and girls.
Tremblay is in custody and scheduled to appear in court for a bail hearing on Jan. 23, 2012.