Her bid to snare the marginal seat of Lindsay from the Coalition was rocked when a series of old Facebook posts surfaced in which she claimed politicians “lie, steal, cheat and use other people’s money to go on holidays”.

But just two weeks later to a room full of Labor faithful in the Western Sydney seat, as MC of the event, Husar joked that she used to bag politicians on social media but now felt so strongly about the “terrible” Coalition government she had to act.

Now Husar has catapulted herself front and centre of Shorten’s by-election campaign — but this time it’s no joking matter.

An unravelling scandal kicked off last week when it was revealed NSW Labor had commissioned barrister John Joseph Whelan to conduct an investigation into Husar, looking at allegations of bullying, harassment, intimidation and misuse of electorate staff.

It comes at the worst possible time for the federal Labor leader as he faces a tough fight to hold on to two battleground seats in Queensland and Tasmania, where voters go to the polls today for the Super Saturday by-elections sparked by Labor’s dual citizenship fiasco.

It is a test which, if Labor fails, could cost Shorten his own job.

Since the investigation into Husar’s conduct hit the headlines there has been a daily drip feed of new and highly damaging claims.

First came further details of the allegations, including that she had told a male staff member to do her dishes so he could learn about “white male privilege”, and that she made her staff babysit her children as well as walk her dog and clean up its faeces.

It also sparked a string of questions over what she was charging to the taxpayer credit card for chauffeurs around Sydney, an interstate trip and household items.

Some former employees told The Daily Telegraph this week about their difficult time working in her office while others feared making comment.

Since the story broke, Shorten, whose wife Chloe is understood to be good friends with Husar, has been under intense pressure to reveal when he found out about the problems and why he did not intervene sooner.

Senior government minister Simon Birmingham laid the boot in on the campaign trail in the knife-edge Queensland seat of Longman.

“If Bill Shorten is serious about the concerns he says he has for worker exploitation, has he spoken to Emma Husar’s staff about their claims and allegations they were bullied in the workplace?” Birmingham said this week.

Shorten has stood by his embattled MP, and while he confessed he “wouldn’t ask anyone else to pick up my dog’s poo” he said he was “happy” to let the investigation play out.

Shorten claims he only became aware of the Husar allegations when his office received questions about the investigation, which was launched in March, from the media last week.

It follows revelations in The Daily Telegraph that a senior operative for the NSW Right was recruited by Husar’s office more than a year ago to try to clean up the staffing “mess” created by high turnover.

Embarrassingly, even Shorten’s leadership rival Anthony Albanese has now revealed he found out about the investigation weeks earlier because it was being openly discussed at a Labor Party meeting.

When asked if it was “surprising that you’ve known for a few weeks but Bill Shorten says he found out last week”, Albanese pointedly replied: “Well, I got asked a question and I gave an honest answer.”

Prime Minister Malcolm Turnbull said Shorten’s insistence he was not aware of the allegations until last week “stretch credulity”.

Husar was born and raised in Penrith and worked a range of odd jobs until becoming a staffer for Labor MP Ed Husic.

She ran unsuccessfully for the state seat of Penrith in 2015. As a first-term MP she rose to public prominence quickly.

On paper she is the perfect candidate: female, single mum of three kids, Western Sydney battler, disability campaigner. Not your typical politician.

It was this that sources have said attracted the local Labor branch members to support her candidacy despite only having been a party member for two years, and to stand by her when questions were raised in the selection process which meant she wasn’t formally endorsed for five months.

She was backed by former NSW ALP general secretary Jamie Clements and lists current secretary Kaila Murnain, as well as powerful union bosses Alex Claassens and Russ Collison, as close allies.

A speech she delivered in November 2016, less than six months after being elected, attracted national headlines.

She stood up in Parliament and gave a heartbreaking account of her experience with domestic violence.

“The first 13 years of my life were marred with physical domestic violence committed towards my mother at the hands of my always drunk and abusive father,” she said.

“Whilst the blows that landed on my mother during my childhood did not land on me physically, they might as well have.

“Sadly, the wheel of domestic violence continues to affect my life as a grown woman with children of my own. The last 16 years of my life have been and continue to be affected by domestic and family violence.”

At an event that night, Shorten described the speech as a rare moment in Parliament — it was taken from a place of work and lawmaking to a “place of inspiration”.

“What I suspect, Emma, is that other women will feel the power to leave relationships, other kids will be able to talk about what’s happened … you were simply magnificent and you reminded us all not only of family violence but why we do our jobs,” he gushed.

But this week The Daily Telegraph revealed Husar’s eldest daughter moved in with her father Peter Fenton after an ­altercation between mother and daughter that sparked a police investigation.

Fenton said he was sure “the truth will one day come out”.

A Labor source close to the electorate says branch members are “shocked” by the raft of allegations against Husar.

“Everyone thought Emma was wonderful but now the facade has began to crack,” the source says.

“The issues became obvious with the constant stream of good people leaving her office.”

Husar commented on the initial story to say she was “horrified” to learn she was being investigated.

Since then she has gone to ground other than to release a statement to declare she was taking “personal leave”.

“The assertions that have been made do not reflect who I am or how my office operates,” Husar said.

“My office is a professional­ and respectful workplace. It should not be perceived in any other way, and of course I am sorry if any person has been given reason to think otherwise.

“I am a single mum with three children, working hard and doing my best. If I have let anyone down, I apologise.”

As the investigation draws to a close, Labor insiders are already working on a plan B for Lindsay, with one of Husar’s former staffers, Liam Rankine, being considered as a potential replacement.