The latest RCMP court filings have turned the spotlight on alleged communications between a Conservative senator and a partner at the auditing firm that investigated Senator Mike Duffy's expense claims, adding another layer to the developing expense controversy.

Even to seasoned political watchers, it has been a challenge to follow who has said what during this crisis.

Here is a timeline of events, statements and comments made by some of the key players involved in the issue, including Duffy, Prime Minister Stephen Harper and his former chief of staff, Nigel Wright.

Feb. 11, 2013: According to information uncovered by CBC News in November 2013, Nigel Wright met with Mike Duffy on Feb. 11 across from Parliament Hill in the Langevin Block, in a room near the prime minister's office, and told him that despite previous assurances that his expenses were legitimate, he would have to pay back the money. Duffy protested, arguing that he had done nothing wrong and asking to have a meeting with Harper. According to multiple sources, Wright said he'd arrange a meeting in 48 hours. 

Feb. 13: At a Conservative caucus meeting in the Centre Block of Parliament, half a dozen MPs, including Dean Del Mastro, Pierre Poilievre and Mark Warawa, voiced their support for Duffy, saying he had been smeared by media reports and the party should stand behind him.​ Harper, however, was adamant that anyone with improper expenses should either pay them back or leave. 

After the meeting had ended, Harper, Duffy and Wright stayed behind and talked further with only security and logistic personnel present. Duffy again made the argument that his expenses were legitimate. Harper said it wasn't about right or wrong but rather about perception, multiple sources say. The public wasn't buying explanations and Duffy had to pay the money back, Harper told him.

Harper has denied saying this, but has said he ordered Duffy to pay back ineligible expenses. There was no discussion about where the money would come from, one source told CBC News, and the meeting ended with Harper saying Wright would make the arrangements.

The Prime Minister's Office has called the comment about the arrangements "categorically false."

May 9, 2013: During question period in the House of Commons, Harper addresses the expense scandal, saying, "Duffy some months ago repaid the money."

May 16: Duffy quits the Conservative caucus to sit as an independent senator "pending resolution" of the expense questions.

"Throughout this entire situation I have sought only to do the right thing. I look forward to all relevant facts being made clear in due course, at which point I am hopeful I will be able to rejoin the Conservative caucus," Duffy says in a statement.

May 19: Nigel Wright resigns as Harper's chief of staff, following revelations he wrote a $90,000 cheque to cover Duffy's expenses. Wright says that his actions were “intended solely to secure the repayment of funds, which I considered to be in the public interest, and I accept sole responsibility.”

Wright adds that he “did not advise the prime minister of the means by which Senator Duffy's expenses were repaid, either before or after the fact.”

Harper says in a statement that he accepts Wright’s resignation "with regret," but that Wright “believed he was acting in the public interest, but I understand the decision he has taken to resign.” (Note: On Oct. 28, the Prime Minister said in a radio interview that, "As you know, I had a chief of staff who made an inappropriate payment to Mr. Duffy. He was dismissed.")

May 22: Speaking in Peru, Harper tells reporters that he did not know about Wright’s payment for Duffy's expenses before the story broke in the media, and says he's "extremely angry about it."

"I learned about this after stories appeared in the media last week speculating on the source of Mr. Duffy's repayment," he says. "I think what's more important is not simply that I did not know, but that I was not consulted. I was not asked to sign off on any such thing, and had I obviously been consulted or known, I would not have agreed with it."

"My belief here was reasonable, and what I think anybody would have expected, that when it was said that Mr. Duffy had repaid his expenses, that indeed he and not someone else had repaid his expenses.

"In terms of my own office, it was Mr. Wright’s money, it was his personal money, that he was repaying to the taxpayer on behalf of Mr. Duffy," he says. "It was his personal decision and he did this in his capacity of chief of staff, so he is solely responsible and that is why he has resigned."

"I know Mr. Wright assisted him or did this for him because he wanted to see the taxpayers reimbursed. That's the right motive, but nevertheless it was obviously not correct for that decision to be made without my knowledge or without public transparency."

"That is why I accepted the resignation of my chief of staff," the prime minister says. "My point is on this that there is accountability when these things happen."

May 23: Duffy tells reporters he wants a "full and open inquiry" about the Senate scandal.

"I think Canadians have a right to know all the facts and I'm quite prepared in the appropriate place and time to give them the whole story," Duffy tells reporters as he leaves the Senate and walks to his car. "There are bits and pieces out there, it should all be put together in one place and there will be some place to do that."

May 28: Harper takes questions about the Duffy affair for the first time in the House of Commons. When asked by Opposition Leader Tom Mulcair what instructions he gave to Wright or other people in his office to solve the problem of Duffy’s expenses, Harper says, “I did not give any such instructions. It was my opinion that Mr. Duffy was to pay his own expenses, and that is what I believed until May 15.”

"Mr. Wright accepted full responsibility for his error in this matter. He offered his resignation, and I accepted that resignation."

Harper also says that on Wednesday, May 15, "Mr. Wright told me that he had given a personal cheque to Mr. Duffy so that he could reimburse the taxpayers. Until that moment, I thought that Mr. Duffy had paid his own expenses.”

May 31: Then-parliamentary secretary for the Minister of Transport, Pierre Poilievre, tells the House that Harper told Duffy in February that any expenses that were inappropriate should be repaid, the first confirmation that the prime minister personally spoke to the senator about the issue.

Later that day, Harper’s then-spokesman, Andrew MacDougall, confirms this, telling the Toronto Star, “Mr. Duffy approached the prime minister in the caucus room regarding the situation with his expenses. The PM was adamant that he should repay any inappropriate expenses. This was the only time Duffy raised expenses with the PM.”

June 4: During question period, Harper is asked who was present when he asked Duffy to reimburse his expenses. Harper makes no mention of whether Wright was in attendance, saying that “my views were known to the entire caucus." Harper says Duffy approached him to "seek some clarification" and that he was adamant that any inappropriate expenses should be repaid. 

June 5:  Mulcair repeatedly asks Harper if Wright was present at the meeting with the prime minister and Duffy. Harper only says that he made his view, that inappropriate expenses should be repaid, known “to the entire caucus and all my employees.”

Harper repeats that Wright took action "on his own initiative" and that "these actions are his sole responsibility. But the prime minister also adds that Wright's decisions "were not communicated to me or to members of my office."

July 5: Court documents released appear to contradict the prime minister's comments in the House that Wright's decision to repay Duffy's expenses were not known by the PMO. According to the documents, Wright informed the RCMP on June 21 that he told four people, including three members of the PMO, about the cheque he was going to write. Those people were Conservative Senator Irving Gerstein; Wright's assistant, David van Hemmen; Chris Woodcock, the then-director of issues management in the PMO; and Harper's then-legal adviser, Benjamin Perrin.

The documents also reveal that the RCMP met with Wright's two lawyers on June 19. Wright’s lawyers tell the RCMP that there was no written contract between Wright and Duffy, but that Wright asked for two conditions to be met in return for the $90,000: that Duffy stop talking to the media and that he reimburse the government immediately. 

July 7: Harper stands by his past comments about the Duffy senate expense scandal, but adds that when he answered questions about the issue in the House of Commons, he answered them "to the best of my knowledge."

Oct. 21: Duffy's lawyer, Donald Bayne, says Duffy's expenses were cleared by the office of  Conservative Senator Marjory LeBreton, who was then Senate government leader. Bayne says Duffy was threatened and pressured by the PMO to repay the expenses or face removal from his seat.

Bayne also says Duffy was told the issue was becoming a "political embarrassment to their Tory base." Bayne says that the PMO came up with a "scenario" and communication lines for Duffy when explaining to the media why he was paying back the expense money.

Oct. 22:  Duffy tells the Senate that both Harper and Wright met with Duffy after a Feb. 13 caucus to discuss the expense controversy, the first time someone puts Harper and Wright in the same room together discussing the issue. Duffy says that Harper told him to repay his claimed expense money because it was the perception of the "base" that was important, not what Duffy said about his own innocence.

"The prime minister wasn't interested in explanations or the truth. 'It's not about what you did, it's about the perception of what you did that's been created in the media. The rules are inexplicable to our base,''' Duffy says Harper told him.

Duffy says he said didn't have the money to repay the expenses, to which Duffy says Wright replied, "'Don't worry, I'll write the cheque.'" However, Duffy doesn't make it clear whether Harper was party to or knew of that conversation.

Following Duffy's comments, Jason MacDonald, a spokesman for the PMO writes: 

"It’s on the public record. Following a caucus meeting Mr. Duffy approached the Prime Minister and raised his expenses. The Prime Minister made it clear that any inappropriate expenses should be repaid. That’s it. That is the only time the Prime Minister discussed Mr. Duffy’s expenses with him. 

Oct. 23: During question period, Harper denies that he ever threatened Duffy with expulsion. Harper adds that he "absolutely" did not say that the issue with Duffy was about perception and not about what he did.

Oct. 24: Harper, who told the House on June 5 that Wright's decision regarding the $90,000 cheque "were not communicated to me or to members of my office," now says that "very few people" knew about the deal. Harper did say in July that that when he had answered questions about the issue in the House of Commons, he answered them "to the best of my knowledge."

Oct. 28: Appearing before the Senate, Duffy alleges the prime minister's former chief of staff arranged for not one cheque to him, but two. Duffy tells the Senate he has a cheque, negotiated by Nigel Wright, in the amount of $13,500 to pay for his legal fees, on top of the $90,000 from Wright to be used to repay his expenses. Duffy said he has the emails and the cheque stub to prove it, adding the $13,500 was paid by the Conservative Party's top lawyer, Arthur Hamilton. Later the same day, the communications director for the Conservative Party confirmed it had paid Duffy's legal fees.

Subsequently, a spokesman for the prime minister issued a statement reacting to Duffy's revelation about how his legal bills were paid by Hamilton. Jason MacDonald said, "Nigel Wright is on the record naming those he informed of his arrangement with Mr. Duffy, and he's assumed sole responsibility for his actions. The prime minister was not aware of the arrangement and had it been presented to him he would not have approved of such a scheme."

Duffy also tells the Senate that the PMO, anticipating that the media would ask where he got the $90,000 to pay his expenses back, concocted an explanation. He said when the PMO heard he had been using a line of credit to renovate his home in Cavendish, P.E.I., they suggested he go to the Royal Bank of Canada and borrow the cash to pay off that line of credit. He alleged the PMO said that he could then tell the media that he took out a loan at the Royal Bank to pay the $90,000.

"Well, that's technically correct, we took out a loan, but that loan wasn't to repay money, the $90,000 that the PMO agreed I didn't owe," Duffy told the Senate. "That line was written by the PMO to deceive Canadians as to the real source of the $90,000."

Duffy claims that he had "reluctantly agreed" to go along with the scheme, that the script was written and emailed to him by the PMO and that the lines he would use with the media were "rehearsed with me right up until minutes before I went on television."

Meanwhile, in a radio interview the same day, the Prime Minister said, "As you know, I had a chief of staff who made an inappropriate payment to Mr. Duffy. He was dismissed." This contradicted Harper's May 19 statement that Nigel Wright had resigned.

Oct. 29: Harper tells the Commons, "Once again, Mr. Speaker, on our side, there is one person responsible for this deception, and that person is Mr. Wright. Mr Wright by his own admission. For that reason, Mr. Wright no longer works for us."

Harper also says, ""The reality is that Mr. Duffy still has not paid a cent back to the taxpayers of Canada. He should be paying that money back.... The fact that he hasn't, the fact that he shows absolutely no regret for his actions, and the fact that he has told untruths about his actions means that he should be removed from the public payroll."

Nov. 2: Conservative Senator Irving Gerstein says he told Nigel Wright the party wouldn't pay for Mike Duffy's disputed Senate expenses. Gerstein chairs the Conservative Fund of Canada, the party's fundraising arm. RCMP court filings have alleged Gerstein was discussing the possibility of paying back up to $30,000 of Duffy's expenses, but this is the first time anyone from the party has mentioned the discussion.

Nov. 4: A Nov. 1 letter obtained by CBC News indicates the RCMP are looking for a chain of emails and documents that support Mike Duffy's allegations that the Senate expenses scandal reaches right into the Prime Minister's Office. "The existence of such documentation may potentially be evidence of criminal wrongdoing by others," wrote Supt. Biage Carrese from the RCMP National Division.

The letter indicates the Mounties are particularly interested in Duffy's claim that his initial story about repaying his disputed expenses by taking out an RBC loan was concocted by senior advisers to Prime Minister Stephen Harper. "Emails from the PMO specifically relating to a script for Senator Duffy to follow in advance of obtaining funds from a RBC loan to repay the Receiver General" may be material to the RCMP's investigation, Carrese wrote.

Nov. 5: The Senate votes to suspend Brazeau, Duffy and Wallin without pay for the remainder of the Senate session, but allows them to keep their medical benefits.

Nov. 20: Court documents, which were filed so a judge would sign a production order requiring the Senate to hand over emails from Duffy and three senators among the Conservative leadership in the Red Chamber, indicate that Wright is being investigated for bribery, fraud and breach of trust along with Duffy, in an RCMP probe that has expanded to include the Prime Minister's Office.

The RCMP allege that senior staffers in Harper's office were working closely with Conservative senators to make Duffy's expense problems go away. The documents also suggest Conservative Senator Irving Gerstein tried to manipulate an indepedent audit of Duffy's expenses by calling Michael Runia, a partner at Deloitte, which was conducting the audit. At Gerstein's behest, Runia in turn called a more junior Deloitte employee to glean information about the audit, the documents allege.

Nov. 22: Prime Minister Stephen Harper says neither he nor anyone in his office gave Senator Irving Gerstein the green light to contact the auditing firm of Deloitte about Senator Mike Duffy's expenses audit. But emails obtained by the RCMP in court documents released earlier in the week revealed that Harper's former chief of staff Nigel Wright did ask Senator Irving Gerstein to contact Deloitte and sort the matter out.​

Nov. 28: The Senate's internal economy committee, which dealt with Duffy's ineligible expense claims, meets to question three Deloitte auditors about potential interference in their audit. However, neither Gerstein nor Runia was invited to the meeting.

Dec. 1: Emails from Benjamin Perrin, a former lawyer to the Prime Minister's Office who allegedly knew about a deal between Nigel Wright and Senator Mike Duffy, are turned over to the RCMP.

The Privy Council Office, which is the arm of the civil service that works with the PMO, had previously told the RCMP and the PMO that Perrin’s emails had been deleted when he left his position in March. In fact, Perrin’s account had been frozen “due to unrelated litigation.”