Racing Integrity Unit general manager Mike Godber told said yesterday the investigation had been completed.
But the decision on whether to charge the Dunns has been delayed for two weeks after Robert Dunn requested more time for a private investigator he has enlisted to complete his own inquiries.
The private investigator, Simon Lamond, a former Christchurch police detective now based in Auckland, refused to talk to The Star.
But his brother-in-law, controversial restaurateur and former jockey Leo Molloy, who is also making inquiries for the Dunns, believed the horses had been nobbled. Mr Molloy is the sister of TV reality queen Dame Julie Christie – the wife of Mr Lamond.
"There is zero chance they weren't nobbled," said Mr Molloy.
"I don't think anyone believes the Dunns did it.
"It's an unfortunate situation. All I will say is that I hope whoever did it is held accountable.
"My role is very minor and I really have little to offer. I have strong feelings about it but not always based on cold, hard facts."
West Coast-born Mr Molloy is a former jockey-turned-veterinarian who became a millionaire with his first venture into the hospitality trade, a student bar called the Fat Lady's Arms in Palmerston North. He then co-founded the popular Euro Restaurant and Bar in Auckland's Viaduct Harbour.
Mr Molloy has also previously helped trainers under investigation by the Racing Integrity Unit.
But he is often in the headlines for all of the wrong reasons, including launching a string of personal attacks against a tattooed man who was denied service at a bar he owned on the Viaduct Harbour and getting into a heated Facebook stoush with a MasterChef contestant.
Mr Molloy and Mr Lamond would not say who had engaged them to investigate.
Said Mr Lamond: "Talk to Robert Dunn."
Neither Robert or John Dunn returned calls to The Star.
But when The Star spoke to Robert Dunn in July he suspected foul play and believed that the horses had been nobbled. He was not at the race meeting in Nelson when the horses returned positive swabs.
He has been based at his Pukekohe stables for the past five years, with John overseeing the Woodend stables where three of the four horses were from.
- Star.Kiwi