TORONTO - Two former top political aides will find out on Friday whether they are criminally responsible for the destruction of documents related to Ontario's gas plants scandal.

Ontario court Judge Timothy Lipson is set to deliver his verdict in the case of David Livingston, chief of staff to former Liberal premier Dalton McGuinty, and his deputy Laura Miller who are accused of attempted mischief and illegal use of a computer.

The verdict comes just months before McGuinty's successor, Premier Kathleen Wynne, will lead her party into a provincial election.

The Crown had earlier dropped a charge of breach of trust against the pair, while the defence lost its battle to have Lipson issue an acquittal on the other two charges they face. The judge did reduce the mischief charge to attempted mischief.

Over several weeks last fall, prosecutors outlined their case in which they claimed the duo had gone to "extraordinary lengths" to wipe the contents of hard drives in the premier's office to ensure no records existed related to the cancellation of two gas-fired power plants.

The cancellation, just ahead of the 2011 provincial election, ended up costing taxpayers more than $1 billion and caused a huge political scandal.