The detective who blew the whistle on his alleged drug-dealing boss was removed from his squad and investigated before senior police took his concerns seriously.
Michael David Blowers, a former detective sergeant, was later charged with supplying methamphetamine and selling cannabis while in charge of the organised crime unit in Northland.
When Blowers' identity was made public, Northland's top officer said the probe which led to the prosecution began after a concerned member of staff came forward.
But the Weekend Herald can reveal the officer was removed from Blowers' organised crime squad and put under strict supervision after he gave senior police management a report on his boss' movements.
Disappointed colleagues say the disciplinary action undermines police attempts to encourage a culture where inappropriate conduct is reported to management without fear of reprisal.
The detective became suspicious of Blowers' behaviour and tailed his visits to the home of a Whangarei woman before handing a dossier - which included covert photographs - to senior CIB management.
But instead of immediately probing Blowers' movements, police management removed the whistleblower from the organised crime squad and placed him under strict supervision.
He was also subjected to an internal code of conduct inquiry which centred on his use of the National Intelligence Application computer system, which is supposed to be used only on official police business.
Several weeks passed until the detective was cleared of any breaches and attention later switched to Blowers, who became the subject of an internal inquiry.
This was elevated to a criminal inquiry when the woman he was visiting told police he gave her methamphetamine and cannabis taken from the police exhibit locker between June 2011 and June 2012.
He was arrested in April and has denied the charges. At the time, Superintendent Russell Le Prou, the Northland district commander, said the inquiry started when a member of staff came forward with concerns. A source within the Northland police took exception to the statement.
"It's absolute bull****. [Northland CIB] looked at this detective really hard before deciding to look into [the allegations against] Blowers. It was being swept under the carpet until common sense prevailed."
In a statement to the Weekend Herald, Mr Le Prou said he could not comment on the treatment of the whistleblower as "internal employment matters" were private between employer and employees.
"As I have stated before, a member of police did have the courage to come forward with concerns about a colleague. These concerns led to an investigation and resulted in some serious charges being laid.
"Northland staff can have confidence that if they do come forward it will be treated seriously."
But the revelations will damage police efforts to build a culture where inappropriate conduct is reported.
Just 58 per cent of Northland police staff are confident they can raise concerns about colleagues without fear of reprisal - 10 per cent lower than the national average - according to a recent workplace survey.
Blowers was a veteran officer with 20 years' experience, with particular expertise in battling the drug trade, and resigned two weeks before his arrest.
He fought to keep his identity secret after his arrest on the grounds that publishing his name would cause "extreme hardship" to his family and in his current job.
Name suppression was lifted last month after a High Court judge said the public interest was "perhaps stronger than usual" because of Blowers' occupation at the time and the nature and circumstances of the charges.
"Moreover, that interest cannot be dismissed as merely prurient; the public has a legitimate right to know about matters potentially impinging on the integrity and proper functioning of our law enforcement agencies and their officers," said Justice Rebecca Ellis.
Blowers has pleaded not guilty and will appear in the High Court at Whangarei again next month.