TORONTO -- The case of two former Ontario premier's top aides facing breach of trust and mischief charges began what may be a long journey through the courts on Wednesday.

David Livingston, who was Dalton McGuinty's chief of staff, and Laura Miller, who was the deputy chief of staff, were charged after a police investigation into the deletion of emails about the Liberals' decision to cancel two gas plants prior to the 2011 election, at a cost of up to $1.1 billion.

Police alleged in court documents that Livingston and Miller hired Miller's partner, Peter Faist -- a computer expert under contract to the Liberals -- who was given a special password by Livingston to wipe clean about 20 hard drives in the premier's office.

Both Miller and Livingston have denied the charges.

Fredrick Schumann, a lawyer for Livingston, said outside court that his client is eager for the case to move forward.

"Mr. Livingston and Ms. Miller have had this hanging over their heads now for 2 1/2 years," he said of the lengthy police investigation.

"David Livingston, certainly, is looking forward to confronting and answering these allegations in court and when he does we're confident that the evidence will show he did nothing wrong."

Lawyers for Livingston and Miller appeared at the court hearing on their behalf. The next appearance has been set for Feb. 24, when the lawyers are expected to schedule a judicial pre-trial -- a closed-door meeting between a judge and the lawyers.

The federal prosecution service was brought in to try the case instead of Ontario's Ministry of the Attorney General. Richard Roy, the Quebec-based federal prosecutor, said he expects the preliminary inquiry will be "longer than usual."

Some of the Crown's evidence was disclosed to the defence lawyers Wednesday, but Schumann flagged some missing items. He said it was somewhat surprising to find items missing after a 2 1/2-year investigation.

Miller has hired high-profile lawyer Clayton Ruby to defend her. His co-counsel, Annamaria Enenajor, said she had nothing to add to a statement that Miller released when the charges were laid in December.

In that statement, Miller accused the OPP of having a bias against her because of a complaint she filed with the Ontario Independent Police Review Director and said she would vigorously defend against the charges.

Miller has raised more than $62,000 through a crowdsourcing website for her legal defence.

The Ontario Liberal Party said it has not paid any of her legal fees. A spokeswoman would not explain why the party paid some of the legal fees for a veteran Liberal fundraiser who is charged in a Sudbury byelection case, but not for Miller.

The party paid some of Gerry Lougheed's legal bills before he was charged with one count of counselling an offence not committed and one count of unlawfully influencing or negotiating appointments. His next court appearance is March 31 in Sudbury.

Lougheed is accused of offering a would-be Liberal candidate for a byelection last year a job or appointment to step aside for Premier Kathleen Wynne's preferred candidate.