One of the alleged incidents of harassment linked to Justin Trudeau's sudden decision to suspend two of his MPs for "personal misconduct" happened on Parliament Hill about a year ago, CBC News has learned.

Although more information has come out about the nature of the allegations and how they became public, questions remain.​ Here's what we know:

1. Who made the allegations?

Two sitting female MPs from the NDP caucus allege they were harassed. How? We don't know.

One of the MPs approached Liberal Leader Justin Trudeau directly, kicking off a chain of events that eventually saw the person in charge of caucus discipline, Liberal whip Judy Foote, reach out to the two women as well as her NDP counterpart, Nycole Turmel. Both whips met together with the women, and Foote met with the two MPs who were eventually suspended, Scott Andrews and Massimo Pacetti.

It's unclear how many other people were aware of the incidents, but CBC News has learned that both NDP MPs reported the incidents to staff — one to senior staff and one to Turmel. Both refused to go public or formalize their complaints.

Newfoundland and Labrador Liberal MP Scott Simms told CBC News on Thursday that he knew about one of the allegations, but was asked not to say anything. Those involved may have reached out to other colleagues on a confidential basis.

Are there witnesses? We don't know. We don't know if others have been, or will be, contacted to substantiate or provide evidence. We haven't been told if the harassment happened in a public place, at an event or behind closed doors.

We do know the incidents are separate. We also know one of the alleged incidents occurred on Parliament Hill and that it took place about a year ago. 

At this time, we have no information to suggest the two incidents were similar.

2. Why can't we know who made the allegations? 

The short answer is: the women don't want to go public.

Some New Democrats were upset Wednesday when the Liberals disclosed that the allegations came from MPs from another party, potentially compromising their confidentiality.

"My main concern," NDP Leader Tom Mulcair told reporters Thursday, "was to listen to the people who had come forward to us, make sure that we respected their wishes — and their wish was not to be re-victimized, to make sure that what they were telling us was confidential and we respected that."

Media reports have so far not disclosed the names. At least one news organization, however, claims to know who the female complainants are but has not published the names.

It's impossible to assess many things — motives, context, consequences — without knowing who was harassed.

3. How serious are the allegations?

Trudeau called the "personal misconduct" allegations "serious," but for now, we have to take his word — together with the judgment of whips Foote and Turmel — that what the women allege warrants suspension.

CBC News has also learned that one MP has made allegations of a more serious nature than the other.

Andrews and Pacetti both issued statements Wednesday expressing confidence that the investigation now underway will find that no harassment occurred. 

Pacetti said he wasn't made aware of the specific allegations against him.

Speaking to CBC Radio's Ottawa Morning on Thursday, Turmel said the women did not want to hurt the careers of the men they were complaining about. Whether that was because they didn't perceive the incidents to be serious enough to warrant a public sanction, or whether they had other motives for feeling this way, is unclear.

4. Why did one MP take her concerns to Trudeau?

Trudeau said in the face of these allegations that he had a "duty to act."

"For someone to come forward directly to a party leader who is not their own, means that there is an expectation that there will be consequences," he said on Thursday from Hinton, Alta.

It's unclear that any specific remedy was proposed to the Liberal leader. The MP who approached him was concerned enough to tell him what happened, but it's unknown whether she asked for something specific to be done.

It's also unclear whether Trudeau considered input from the NDP MPs or their leader in making his own decision about what to do in his caucus and how to announce it.

One MP, Turmel said Thursday, heard about the suspensions on social media as the news broke. Turmel also said the women "didn't want to put a formal complaint" and that Foote was told they "didn't want it to come out publicly without consent."

Whatever they may have hoped would happen, the investigation underway now under the jurisdiction of the Speaker of the House of Commons was triggered by a letter from Foote, not a direct formal complaint from the women.

Turmel met with Speaker of the House Andrew Scheer. He told her human resources would need to be involved and that the women may need to make formal complaints for the process to move forward.

5. What partisan motives may be influencing what happened?

Armchair political analysts all over Ottawa have been wondering why it was Trudeau taking questions in the face of the harassment revelations on Wednesday, while the leader of the complainant MPs, Tom Mulcair offered no details in his short statement after caucus and answered no questions from the press. (Mulcair answered a few questions about the matter on Thursday.)

Mulcair says he isn't saying more to respect the wishes of his MPs.

New Democrats complained about how the Liberals handled the situation. It's unclear, however, what they wanted the Liberals to do, once made aware of serious complaints.

Trudeau said Wednesday that "it's 2014" and he has a "duty to protect and encourage individuals in these situations to come forward." 

Mishandling a harassment allegation could damage his reputation as a leader and cost the Liberals votes. Whether he's overreacted or overreached is impossible to judge without more facts.

6. What does this mean for the newly suspended MPs?

In the short term, Pacetti and Andrews become Independent MPs and lose their critic, caucus and committee roles. They continue to serve their constituencies and sit and vote in the House of Commons.

Over the longer term, it's unclear how quickly the investigation will unfold. Will it end before the next general election, allowing one or both to be reinstated as Liberals and run as incumbents? 

If the investigation is not over, they could not run as Liberals — assuming they even want to run for re-election after this episode.

The constituency associations would need to find new candidates, perhaps on short notice. It's unknown what contingency plans the Liberal leader's office might have for these ridings.