Stephen Harper's current chief of staff, Ray Novak, has been dragged into the criminal case against Sen. Mike Duffy, who is on trial for charges relating to his dubious Senate expenses.

Novak frequently came up as Duffy's defence lawyer, Donald Bayne, questioned former chief of staff Nigel Wright about the PMO's role in handling Duffy's outstanding Senate expenses in 2013. Bayne grilled Wright at length about a string of emails presented in court, which show Wright, Novak and several PMO staffers working with Duffy and a number of senators to keep the situation out of the press.

Novak replaced Wright as Stephen Harper's chief of staff in 2013, after it came to light that Wright had paid $90,000 out of his own pocket to cover Duffy's Senate expenses. However, emails submitted into evidence show Novak was aware of the deal with Duffy.

In a March 23 email to Novak and the lawyer for the PMO, Wright wrote: "I will send my cheque on Monday."

Novak was also on a conference call with Wright, Duffy's lawyer and a lawyer for the PMO in March 2013. However, Harper spokesperson Kory Teneycke says Novak was pulled away from the call before the arrangement was discussed.

Speaking in Hay River, N.W.T. on Friday, Harper deflected questions about Novak, who is currently a key member of the Conservative Leader's election campaign.

"These are the actions of Mr. Duffy and Mr. Wright," Harper said. "You certainly don't hold subordinates responsible for the actions of their superiors."

On Friday, Bayne spent much of his time delving into email chains and highlighting messages where members of the PMO attempted to control the whole situation, either by telling Duffy what to do or by telling senators not to act without their sign-off.

Bayne highlighted one email from Feb. 16, 2013, sent by Wright to the PMO's lawyer and two aides. In the email, Wright wrote: "We'll have to do this in a way that does not lead to the Chinese water torture of new facts in the public domain, that the PM does not want."

Bayne asked Wright what he meant by that email.

“What I call Chinese water torture is the dribbling out of new facts,†Wright said.

Bayne also accused Wright of drafting media statements for Duffy that hid the fact he did not repay the money himself.

"Did your office script lines that said Duffy paid?" Bayne asked in court.

"That was the implication, yes," Wright replied.

At one point during their exchange, Bayne told Wright that he was a “great champion – when it suits you – of common-sense rationale.â€

Before the trial started on Friday, Duffy stopped to answer a reporter’s question outside the Ottawa courthouse.

"You seem to be in a different mood today, Mr. Duffy," one reporter said.

"I'm always in a good mood," Duffy said, before returning to the courthouse for the continuation of his criminal trial.

Duffy faces 31 charges, including bribery, breach of trust and fraud of government, relating to his questionable Senate expenses. He has pleaded not guilty to all charges.

Bayne, spent most of Thursday grilling Wright about his "circle the wagons" approach to dealing with Duffy's case. Bayne also accused Wright of pressuring the senator to take a deal drawn up by PMO staffers to limit the political fallout for the Conservative government.

"This wasn't principles or morals; this was sheer political damage control," Bayne told the court on Thursday.

Wright eventually struck a deal with Duffy to personally cover $90,000 in Senate expenses and legal fees, in exchange for Duffy admitting a "possible error" in his Senate paperwork.

Wright has insisted Stephen Harper was only "broadly aware" of the situation, insofar as he knew the money would be repaid.

In a May 14, 2013 email to three PMO staffers, Wright wrote: "The PM knows, in broad terms only, that I personally assisted Duffy when I was getting him to agree to repay the expenses."

With files from The Canadian Press