The trial of two former senior political aides is hearing from a private IT consultant who was allegedly hired to wipe clean several hard drives in ex-premier Dalton McGuinty's office.
Peter Faist, who is not charged in the case, told the court he signed an immunity agreement before giving a statement to provincial police as part of their investigation.
Prosecutors allege Faist was hired to wipe clean about 20 hard drives in McGuinty's office in 2013.
Faist's common-law spouse, Laura Miller, is one of two people charged in connection with the deletion of emails about the Liberal government's decision to cancel two gas plants just before the 2011 provincial election.
David Livingston, McGuinty's former chief of staff, and Miller, who was his deputy, have each pleaded not guilty to breach of trust, mischief and unlawful use of a computer
The Liberals' decision to cancel the gas plants in Oakville and Mississauga set off a political firestorm.