Former Australian Border Force commissioner Roman Quaedvlieg says he is considering his legal options after a lengthy integrity commission investigation found he acted corruptly.
However, no charges or action will be taken against the 55-year-old former decorated and distinguished Brisbane police detective due to insufficient burden of proof.
The summary findings were formally published by the Australian Commission for Law Enforcement Integrity despite efforts by Mr Quaedvlieg to have them suppressed, claiming it was not in the public interest to do so.
Mr Quaedvlieg, who is a highly experienced investigator, a former ACT chief police officer and an assistant commissioner with the Australian Federal Police, described the commission's investigation as "deeply flawed" and said it offered no rebuttal of his concerns.
The commissioner who led the investigation has since left.
The commission investigation into Mr Quaedvlieg's conduct, labelled Operation Valadon, began in June 2017.
Since then, Mr Quaedvlieg was sacked from his position as Border Force commissioner and has written a "tell-all" account called Tour De Force, which is due to be published next month.
Late last year, Mr Quadvlieg was also a key witness in the same commission's investigation into potentially corrupt activity within Border Force and which involved the Crown Casino group.That investigation is still ongoing.
Operation Valadon investigated eight allegations of corrupt conduct made against Mr Quaedvlieg. Most pertained to the misuse of his influence and position as Australian Border Force commissioner.
Three of the eight allegations were proved. The investigation took testimony from 23 witnesses and the final full report, the contents of which remain undisclosed, is some 200 pages long.
Since Mr Quaedvlieg's departure from Border Force, he has faced withering personal attacks from his former boss, Home Affairs Minister Peter Dutton, over the former commissioner's testimony to a Senate hearing regarding the Queensland au pair visa controversy.
Mr Dutton claimed he had been "smeared" by Mr Quaedvlieg, whom the senior minister then accused in federal Parliament of "grooming a girl 30 years younger than himself".
Mr Quaedvlieg has been embroiled in a lengthy and public controversy around how he used his position as a senior public servant to support an application and appointment to Border Force for his 25-year-old girlfriend, Sarah Rogers.
Ms Rogers gave false evidence to the ACLEI investigation into Mr Quaedvlieg's conduct. In July last year she pleaded guilty to the offence in Sydney's Downing Centre Local Court, and was sentenced to a seven-month intensive corrections order and 100 hours of community service.
The ACLEI findings bookend lengthy and bitter exchanges between the parties.
In a detailed letter, Mr Quaedvlieg expressed his own concerns about the commission's "pre-conceived view of culpability", "biased and selective assessment of 'evidentiary' material", and the "unprofessional behaviour" of its investigators.
In responding to Mr Quadvlieg, the newly appointed Integrity Commissioner, Jaala Hinchlcliffe, said she determined it was in the public interest to disclose the summary of the investigation report.