The confirmation came as Conservatives called for Mendicino's ouster over his office's handling of the information that the convicted killer and serial rapist was being moved out of maximum-security prison.
While his office was informed about the possibility of the transfer to a medium-security institution nearly three months before it happened, Mendicino said he found out about it the day after Bernardo was moved.
"As the minister said in question period, he should have been informed earlier and he has dealt with that," Alison Murphy, a spokesperson for Trudeau, said in a statement.
Murphy said a staffer in Trudeau's office was alerted by the Privy Council Office in March that the transfer was a possibility, and "inquiries and requests for information were immediately made to the public safety minister's office."
The statement did not explain why Trudeau was only briefed about the transfer on May 29.
"Now we know why Justin Trudeau won’t fire his incompetent minister: Justin Trudeau’s own office was alerted in March that Paul Bernardo, one of the most vile monsters in Canadian history, was going to be transferred to medium security to enjoy more freedom and comfort," Opposition Conservative Leader Pierre Poilievre tweeted late Wednesday.
"Instead of acting, the prime minister did nothing and left it in the hands of his most useless minister. This is a failure of leadership at the very top."
Calls for Mendicino's resignation dominated the House of Commons question period on Wednesday, with Mendicino saying "corrective steps" have been taken to prevent a similar situation from happening again.
@JustinTrudeau learned of Paul Bernardo transfer the day it happened, before @marcomendicino knew. #CDNPoli
The lambasting came after the Correctional Service of Canada disclosed the timing of when it first informed the minister's office about the plans around Bernardo.
Spokesman Kevin Antonucci said the correctional service first emailed Mendicino's office about the impending move March 2. At the time, "the final date" for the transfer had not been determined, he said.
The service reached out again on May 25, this time including updated "communications messaging" and information the transfer would happen on May 29.
Mendicino's first public response came on June 2, when he called the decision by the correctional service "shocking and incomprehensible."
That statement made the minister guilty of telling "lies" to Canadians, Poilievre said Wednesday, because his office knew almost three months in advance and Mendicino had already known for days.
"Why has the staff not been fired?" Poilievre asked before his party's weekly caucus meeting.
"Marco Mendicino needs to resign," he added, saying that if the minister refuses to step aside, Trudeau should just fire him.
Mendicino's office did not respond to questions about why staff withheld information from the minister. He did not take questions from reporters.
He also admitted to sexually assaulting 14 other women and was convicted of manslaughter in the death of Tammy Homolka, who died after being drugged and sexually assaulted.
Tammy was the 15-year-old sister of Bernardo's then-wife Karla Homolka, who was released in 2005 after completing a 12-year sentence for her role in the crimes committed against French and Mahaffy.
Mendicino, speaking in French, told the Commons "it was a mistake within my office" not to inform him when the federal correctional service first presented it with the information.
"I have also made it clear to my staff that this should have been briefed immediately, corrective steps have been taken, I have dealt with it and we will now always defend the rights of victims," he told fellow MPs in English.
He separately announced plans to issue a directive to the correctional service that the public safety minister "must be formally and directly notified … in advance of the transfer of any high-profile or dangerous offenders."
He said in the House that a directive will also ask that the service "puts victims' rights at the centre of decisions to transfer" and informs their families before transfers take place.
A review is currently underway into the correctional service's decision to transfer Bernardo, who it says does not pose a threat to public safety.
Antonucci said he expects that review to be finished "within a few weeks."
A three-person panel will probe the "appropriateness" of his new classification, the consideration and notification given to his victims and "whether the legislative and policy framework was followed," he said.
Tim Danson, the lawyer representing the French and Mahaffy families, said Wednesday marked a troubling anniversary.
"It's particularly acute," Danson said. "We're into this controversy on the very day that Paul Bernardo abducted Leslie Mahaffy."
Danson said he spoke with Mendicino on Wednesday morning and they had what he characterized as a "frank but constructive conversation."
He says the victims' families are "very, very troubled" by the minister's lack of notification, saying the incident demonstrates a "cavalier attitude" toward the situation and "demeans" the memories of their daughters.
Danson also questioned how it could be possible that staff in the minister's office did not notify him in advance of Bernardo's transfer, given Bernardo's notoriety and brutal criminal past.
"Is this about plausible deniability?" he asked.
He and Poilievre have both insisted that Mendicino has the power to reverse Bernardo's transfer through a ministerial directive.
Poilievre has said that those convicted of multiple murders should always have to serve out their full sentences in maximum-security institutions.
The minister has repeatedly said that his office does not wield power over the security classification for inmates since the correctional service operates as an independent institution.
Mendicino suggested to the Commons that Poilievre's suggested solution of taking direct action in the matter would amount to "political interference."
NDP Leader Jagmeet Singh told reporters that firing or demoting the minister is not the answer, saying he believes this was an example of the Liberal government being lousy when it comes to information-sharing.
He instead laid the blame at the feet of Trudeau and said there are legitimate concerns about how the minister has handled his portfolio, which includes the Liberals' controversial gun legislation.
"It doesn't look like he's got his house in order," Singh said.
"I just don't want to let the prime minister off the hook. I want to make it very clear the prime minister sets the tone."
Some top Liberals, such as government House leader Mark Holland, also expressed concern about how information flows within government.
"It's good for us to take a look at making sure that we have the right processes in place to deal with the flow of information in a country as large and as big as this. There is an enormous amount of information in this form," Holland said.
"So we do have to review our processes and make sure that they're as strong and as rigorous as possible, and where communication gaps exist, that's an opportunity to look at how to fix it."
Asked about the need for staff to be disciplined, backbench Liberal MP Chris Bittle said he understands why that would make sense.
"The gut reaction would be: of course. But I'm sure this (is a) staffer that may be overworked, that probably feels about one foot tall and wants to crawl under a rock."
This report by The Canadian Press was first published June 14, 2023.