The fate of former MP Rick Dykstra's candidacy for the Conservative Party was settled during a conference call with former prime minister Stephen Harper in the fall of 2015, CBC News has learned.

The party was grappling with what to do about a sexual assault accusation against the incumbent Conservative MP.

A source familiar with the campaign, who spoke to CBC News on condition of anonymity, said it was a difficult conversation that went "around the block a few times."

Ultimately, it was up to Harper, as party leader, to make the decision.

In a statement released on Friday night, Harper said he "understood that the matter had been investigated by the police and closed a year prior."

"Given this understanding of the situation, I did not believe that I could justify removing him as a candidate," the former prime minister said. "Recently, much more information has come to light, including information to the effect that the original investigation may not have been complete."

Dykstra's candidacy has been the subject of questions since Maclean's magazine reported he was accused of sexual assault in 2014. The allegations have not been proven and Dykstra's lawyers have told Maclean's that the allegations are "false."

In a second report on Friday, Maclean's revealed internal emails in which Jenni Byrne, the campaign manager, tersely raised questions about Dykstra's candidacy.

According to emails seen by CBC News and verified by multiple sources, Guy Giorno, the campaign chair, responded to one of those emails by reiterating that Arthur Hamilton, the Conservative party's lawyer, "should be tasked to review."

"I thought that is what we had already asked for," Byrne responded.

"Apologies. Good," wrote Giorno.

According to the emails published by Maclean's, details of Hamilton's conversation with Dykstra, including the fact police had investigated and closed the file, were relayed within the campaign team the next day, on Sept. 8, 2015.

Internal dysfunction

The source familiar with the campaign said, beyond the Dykstra situation, there was a great deal of internal dysfunction and unhappiness at that point in the Conservative campaign.

The source also suggested that a properly functioning campaign might have acted quicker to investigate a letter sent by the lawyer for Dykstra's accuser in late August.

Signs of that discord became apparent again this week.

In a statement on Saturday, Giorno said that "earlier this week anonymous sources were pushing a false story that the decision to keep Rick Dykstra as a candidate was mine, overruling a senior official with a contrary view."

"I made no such decision. I overruled nobody," Giorno said.

In his own statement, Ray Novak, Harper's former chief of staff, said "the matter was not taken lightly by anyone involved."

"This was an extremely difficult decision that ultimately turned on whether a closed investigation without charges was sufficient grounds for firing," Novak said. "Certainly, with the benefit of hindsight and additional information, Rick Dykstra should have been fired as a candidate."

Conservative Party Leader Andrew Scheer has said an independent investigation will look into what happened around Dykstra's candidacy and a report will be made public.

Talking points provided to Conservatives over the weekend and obtained by CBC News said the purpose of the third-party investigation "is to determine what information was known and by whom, how that information was shared, and what process was used to make decisions."

Dykstra lost the riding of St. Catharines in Ontario, but then went on to be elected president of the Ontario Progressive Conservative Party. He resigned late last month, hours before Maclean's published its story with the allegation of sexual assault.