Troy Buswell's chief of staff engaged in misconduct when she gave misleading information to a WA government inquiry into his 2014 car crashes, the corruption watchdog has found.
The former transport minister smashed his ministerial vehicle into several cars on his way home from a wedding in the early hours of February 23 that year, possibly while drunk, but Rachael Turnseck took steps to protect him from the consequences.
Mr Buswell, who was also the treasurer, resigned from his ministerial positions the next month and quit parliament altogether in September 2014, all the while seeking treatment for mental illness. Ms Turnseck has also left the public service.
The Corruption and Crime Commission (CCC) concluded in a report tabled in parliament on Wednesday that she put her loyalty to Mr Buswell above her duty to the state because she knowingly and intentionally provided misleading information to an internal inquiry.
"In seeking to protect Mr Buswell from the consequences of his actions, Ms Turnseck's own actions caused her to cross the line," the CCC said.
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"Her actions were contrary to the fidelity she owed, and duties incumbent upon her, by virtue of her employment."
According to the report, Ms Turnseck gave evidence that she believed Mr Buswell would have been over the limit when he drove himself home that night and, after inspecting the damage to his car the next morning, she took a lead role in liaising between him and others.
"Ms Turnseck effectively controlled the amount of information that was provided about Mr Buswell's health, the severity of his condition at the time, and controlled who knew about the vehicle damage," the report read.
"Ms Turnseck had numerous opportunities to report Mr Buswell's behaviour and the vehicle damage through her meetings with the premier and his staff."
The CCC also found Ms Turnseck omitted mentioning the involvement of Leo Gibbons, who was Mr Buswell's electorate officer and initially claimed he knew nothing of the smashed car until the story broke in the media.
He later changed his evidence, admitting she had told him about the crashes the morning after and the fact Mr Buswell had been drinking heavily the night before.
Opposition treasury spokesman Ben Wyatt asked Premier Colin Barnett during question time why Mr Turnseck was not previously deemed to have breached the state government's code of conduct.
Mr Barnett said Mr Wyatt was being insensitive and had wrongly accused his office of a cover-up.
"Troy Buswell was extremely unwell," Mr Barnett said.
"In that immediate time after - and it was my view from what I knew - the care of everyone close to that situation was about Troy Buswell's health. And it was serious.
"That may well have clouded the judgment of Rachel Turnseck.
"I think anyone who's got an element of decency can understand that situation."
Mr Barnett said he was not defending the behaviour of Mr Buswell or Mr Turnseck but she was under a lot of stress while he was in the midst of a mental health crisis, so the opposition should show some compassion.
"And no way did she act in self interest at all," the premier said.
In the wake of the crashes, Mr Buswell was convicted of 11 traffic offences, fined $3100 and disqualified from driving for one year but he was not charged with drink driving because he did not undergo a breathalyser test.
