Blogger Cameron Slater asked an ex-prostitute friend to help dig up more stories on Auckland Mayor Len Brown when it became clear he was not going to resign after his extramarital affair became public, Nicky Hager says in his book Dirty Politics.
The book contains a chapter on the sex scandal, which Slater broke on his Whaleoil blog site three days after Brown was re-elected mayor, and which Hager calls "his most spectacular operation to date and also the grubbiest".
Slater, said the author, believed it was his personal responsibility to help get a right-wing mayor elected in 2013 after Brown defeated Auckland City mayor John Banks in the first Super City election in 2010.
His method was a sex scandal launched on October 15 when intimate details of an affair between Brown and council adviser Bevan Chuang were published on his blog, said Hager.
"On 23 October he asked his ex-prostitute friend if she could help dig up some more stories: 'Rattle your cages to see if Len rooted in brothels'.
"Get me dirt...he will get away with it otherwise...whatever you've got or can rustle up', Slater is alleged to have said in Facebook messages with the friend.
In the week before Christmas, Hager said Slater contacted the prostitute friend again and asked about the Mustang Gentleman's Club at North Harbour.
"Did Brown use Mustangs?" he asked.
And after the council censured Brown about the affair on December 19, Slater again contacted the friend.
"Right, so lenny the rooter ain't going anywhere...time for some real murk...have a chat to your contacts...time to out his brothel rooting."
Mr Brown had no comment to make about the book.
The chapter also reveals Facebook messages between Slater and former Auckland City councillor and National Party member Aaron Bhatnagar and Auckland councillor Sharon Stewart on October 15, the day he posted the sex scandal.
Mr Bhatnagar hoped the material would be dragged out over a couple of days, to which Slater replied: "Over months."
That evening Mr Bhatnagar messaged Slater again saying some people from the National Party-aligned Citizens and Ratepayers group were asking him "to lay off the Len Brown jokes...it might be damaging", to which Slater replied: "F... off, you owe them nothing, keep kicking him."
Mrs Stewart, a Howick councillor, messaged Slater saying "Oh my godd (sic) - John (Palino) might end up mayor after all", to which Slater replied, "Yup, Tuesday".
In June 2013, Slater chatted with Mrs Stewart, who said: "Who would ever have thought you and I would be Facebook friends".
Hager said Slater was more interested in passing on his thoughts about Brown's right-wing mayoral opponent John Palino's campaign.
"OK..JP (Mr Palino) needs to be careful with donors. He needs good advice, not sure he has it yet...and he needs to get funding for someone to run a third party campaign against Len."
This was about the time, says Hager, that Luigi Wewege, a member of Palino's campaign, was pressuring Chuang to give him usable evidence of her affair, and shortly before Slater and Mr Wewege began working on a plan together.
About this time, too, said Hager, Slater's father - former National Party president John Slater - became Mr Palino's campaign manager.
Mrs Stewart has been a critic of Mr Brown since their days together on Manukau City Council.
She was one of five right wing councillors - the others were Cameron Brewer, Denise Krum, Linda Cooper and Dick Quax - who voted against a motion at last December's censure meeting to keep working with the mayor in the best interests of Auckland.
In February, Mrs Stewart, who is president of the Howick Military Tattoo, told Mr Brown to stay away from the event at Lloyd Elsmore Park because he would attract protesters and take the shine off the Scottish games.
Mr Bhatnagar, who is in California, and Mrs Stewart could not be reached for comment.