Jami-Lee Ross rang local body politicians and threatened to end their political careers in a "Darth Vader voice", it has been claimed.
The embattled former National MP has been at the centre of a number of scandals this week, including allegations of infidelity, bullying, leaking and sexual harassment. He in turn has accused the party and its leader Simon Bridges of corruption and breaking the law.
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Those who've come up against Mr Ross in the past say it's not surprising he's gone "off the rails". David Collings, chair of the Howick Local Board, says he incurred Mr Ross' wrath two years ago in a contentious fight for the position.
Mr Ross' wife Lucy Schwamer wanted to be chair, and quit the board only minutes after being sworn-in, saying she had no confidence in Mr Collings.
"It got very nasty," Mr Collings told Newshub Nation on Saturday. "He actually threatened, attacked my members, for support. For example, my deputy chair [Katrina Bungard] has aspirations - she'd be a great National MP… he's used that over her to try and get his way. Threatening her - 'you're political career will go nowhere' - other members of the board, even a sworn police officer, veiled threats about your employment."
Ms Bungard told NZME on Thursday the intimidation was so bad, she had to get medical help.
Mr Collings said he never received a call from Mr Ross himself, but told Newshub Nation he was privy to one call in which he alleges the Botany MP used a "Darth Vader voice… a bit like Freddy Krueger or something".
"We complained to the National Party, and Greg Hamilton - who was the manager at the time - was quite helpful. He said, 'What you're telling us is not right. An MP shouldn't' be getting involved in something in local government, particularly when his wife is involved.' Greg was quite helpful, but it didn't stop."
He said the party did what it could, but never fully realised "the calamity of this and how bad it was".
"We knew, because we were experiencing it first-hand - we were hearing it from members on a daily basis… Jami-Lee had just gone rogue."
Former National Party general manager Chris Simpson said as an MP, rather than an employee, the party couldn't do much to rein in Mr Ross without a police statement.
"The party always does a lot behind the scenes which the media will never report on," he told Newshub Nation.
"The party is not Parliament. The party is actually a business as well. When I was there, there were 45,000 members - you're running a business, so you have to do that well. However an MP is elected by the electorate, and is responsible to the electorate."
Mr Collings said he got in touch with Newsroom to tell them about Mr Ross, but even he's been shocked by what emerged.
Newsroom reporter Melanie Reid revealed allegations from several women that Mr Ross harassed and bullied them.
"I went to Melanie because she broke the story on Todd Barclay. I said, 'Look, this guy - we've got a guy in our area that makes Todd Barclay look like an angel.' But we knew nothing of this."
Mr Ross has admitted to two cases on infidelity, including one with an unnamed MP. He didn't answer requests from Newshub Nation to appear on the show, and said on Thursday he was assessing his legal options.
Mr Bridges declined to be interviewed.