Oct. 28, 2014 — Liberal leader Justin Trudeau is approached by a female NDP MP who accuses two Liberal MPs, Scott Andrews and Massimo Pacetti, of sexual harassment. She says Pacetti had sex with her without her explicit consent and that a fellow New Democrat had been sexually harassed by Andrews.
Oct. 30 — In a behind-the-scenes meeting with the NDP and Liberal whips, NDP MP Craig Scott tells the Liberals that one of the misconduct incidents, as it was described to him, amounted to an allegation of sexual assault. Scott accompanies one of the complainants to the meeting.
Nov. 5 — Trudeau suspends the two MPs from his caucus. Andrews and Pacetti deny they did anything wrong.
Nov. 19 — NDP leader Tom Mulcair says neither woman should be pushed to lodge formal complaints, no matter how serious the allegations. Mulcair says it's up to them to decide if they want to participate in any investigations.
Nov. 25 — The NDP MP who levelled the allegations tells The Canadian Press she'd be interested in participating in an independent House of Commons harassment probe. That never materializes.
Dec. 5 — Trudeau hires Cynthia Petersen, a Toronto human rights lawyer, to conduct an independent investigation after parties fail to agree on a parliamentary process for resolving complaints between MPs.
March 18, 2015 — Following a report from Petersen, Trudeau prepares to tell Andrews and Pacetti that they're permanently expelled from caucus. The news leaks and Pacetti pre-empts Trudeau's formal announcement to say he won't run in the next federal election. Andrews says he's astounded to hear about his fate in the media..