Prime Minister Jacinda Ardern says she learned only in the past few days that complaints against a Labour staffer were of a sexual nature. So who knew what, and when? Andrea Vance takes a look at how events unfolded. 

One blustery April Friday, a gang of nine young, idealistic political activists climbed into a mini-van to make the long drive north from Wellington to Hamilton.

Just a few weeks earlier prime minister Bill English had announced the general election would take place on September 23.  Former union boss Andrew Little was Labour's leader and trailing in the polls. But the most recent Colmar Brunton poll had given the party a four-point bump, and popular MP Jacinda Ardern had just won the Mt Albert by-election and been appointed deputy leader.

The group were heading to a Young Labour conference at Waikato University. "Help shape the future of Young Labour and hear about our plans for this momentous election!" the invites read.

Spirits on the bus were high: some were preparing for their first election campaign, and Little was due to give a speech to the young delegates. But events over that weekend would change the lives of two of those young volunteers. 

• Acting Labour Party president was on panel which dismissed initial complaints
• Labour staffer at centre of sexual assault claims resigns from Parliament
• Former Labour Party president surprised Jacinda Ardern wasn't told about sexual assault claims
• Haworth's resignation doesn't change anything - PM still must front up

After a series of Saturday workshops on campaigning, some of the volunteers got drunk on wine and vodka. The group split up, and half went into the city, the rest returning to their marae accommodation.

One of the young women, then 18, was increasingly uncomfortable by the behaviour of one of the men. He was an active figure in the party's youth wing. He would come up behind her, hug and grab her, she would later say.

When she tried to fall asleep, she says he nuzzled her neck and swung his leg over her hips. She got up and moved away.

At the time, she didn't consider what had happened to her an assault.