Harper made the comments during a year-end interview with French-language network TVA, during which he seemed to question host Pierre Bruneau's use of the term "lone wolves" to describeMartin Couture-Rouleau and Michael Zehaf-Bibeau.
"It's true that there was only one attacker, but it's not necessarily the case that there was only one guy," Harper said.
"It's possible there were other people who were around these men — and there was an arrest in Montreal — as we have announced already."
Asked directly by Bruneau if he believed there were links with other people, Harper said that the investigations continue.
Teen charged with terror-related offences
In response to queries from CBC News about the basis for those remarks, two separate spokesmen for the prime minister pointed to media reports on terror-related charges being laid against an unnamed 15-year-old Montreal boy who was arrested in October.
"You guys ran this story a few weeks back," PMO spokesman Jason MacDonald told CBC News via email, which he copied to colleague Carl Vallée.
Vallée confirmed that the reference was to the Montreal arrest.
"The authorities have not ruled out the possibility attackers involved in Canada [including Ottawa] could have been in communication with other people," he said by email.
Vallée denied that Harper's statement was based on additional undisclosed information and repeated that he had been referring to the arrest in Montreal.
"That's all," he added. "Moving along."
MacKay quoted making similar comments
This isn't the first time a senior member of the Harper government has questioned the claim that the two recent attacks in Canada were the actions of so-called "lone wolves."
In an article written in response to the hostage-taking in Sydney earlier this week, Bloomberg News reporter Josh Rogin said Justice Minister Peter MacKay told him that Parliament Hill gunman Zehaf-Bibeau "may have been in direct contact" with the Islamic State in Iraq and Syria (known as ISIS.)
“They were influenced by ISIS there is no question,” Rogin reports MacKay saying during the Halifax International Security Forum last month.
Although Rogin quoted MacKay saying he "didn't know for certain" if either man had been communicating with ISIS, the minister reportedly added that government officials "have that suspicion," based on "statements both of those individuals have made to others."
MacKay's office declined to elaborate on the reported comments, but would only point out that Rogin's article used the words "suspect" and "may have."
Also on HuffPost