The Australian Commission for Law Enforcement Integrity will examine how police handled the Parliament House rape case in the wake of explosive claims made by the ACT's top prosecutor, who has accused investigators of "quite clear interference".
ACT Attorney-General Shane Rattenbury revealed the referral on Friday, when he said the territory government was "taking advice" on how to address the increasingly public stoush.
But Mr Rattenbury has also moved to quell fears of a rift between ACT Policing and the Director of Public Prosecutions, saying "professional difference is an acceptable situation".
The Guardian revealed on Thursday that director Shane Drumgold SC had written to ACT chief police officer Neil Gaughan to complain about what he called a "very clear campaign" to persuade him not to prosecute Bruce Lehrmann.
Mr Drumgold claimed he had been "pressured to agree with the investigators' desire not to charge" Mr Lehrmann, who has always denied raping Brittany Higgins in a ministerial office at Parliament House when the pair were Liberal Party staffers in 2019.
The prosecutor said police had cherry-picked and mischaracterised evidence to suggest weaknesses in the case against Mr Lehrmann, then became "clearly aligned with the successful defence of this matter rather than its prosecution".
Mr Lehrmann's trial was aborted because of juror misconduct in October, before the case was dropped last week over fears about the impact a retrial would have on Ms Higgins' mental health.
In his letter, Mr Drumgold also made the claim Ms Higgins had "felt bullied by police" to drop her complaint.
The release of Mr Drumgold's letter, under freedom of information laws, prompted a stinging rebuke from Australian Federal Police Association president Alex Caruana.
Mr Caruana, who accused the top prosecutor of "desperate attempts to smear" the force and its ACT Policing arm, said a judicial inquiry into the affair was "an absolute necessity".
"While Mr Drumgold has called for an inquiry into the actions of police, any inquiry, in the interests of impartiality and holism, must also assess the conduct of Mr Drumgold, the DPP, the ACT Victims of Crime Commissioner, and ACT Attorney-General Shane Rattenbury, as well as issues causing delays in the trial and subsequent mistrial," he said.
Mr Caruana said he wanted to know why Mr Drumgold took the matter to trial if police believed there was not enough evidence and held concerns about how certain material was obtained.
The police union boss also expressed concerns about the release of Mr Drumgold's letter to The Guardian, saying he understood it had not been redacted and it contained the personal details of officers involved in the investigation.
Asked to respond to the controversy on Friday, Mr Rattenbury told ABC radio the contents of the letter were "extremely concerning".
The Attorney-General would not make the same concession in a subsequent interview with The Canberra Times, saying police and prosecutors would sometimes disagree on matters.
"The government's obviously considering the matters that have been raised and taking advice on the steps we'll take from here," Mr Rattenbury said.
"But the police and the DPP have a strong working relationship. They work together all the time and I hope that we can see that continue."
Mr Rattenbury refused to rule out an inquiry into the handling of the case.
Quizzed on whether the seemingly strained relationship between the police and the office that prosecutes on their behalf was tenable, he replied: "I'd encourage the community to look at the broader relationship between [ACT] Policing and the DPP, and to not focus solely on this individual matter."
A short time later, Mr Rattenbury's office provided an official statement.
"I am aware the matter has been referred to [the] Australian Commission for Law Enforcement Integrity," the Attorney-General said.
"As such, it is not appropriate to comment further at this time."
Mr Drumgold has so far declined to comment on his letter, other than to confirm he is aware of its release to The Guardian.
An ACT Policing spokesman also said police knew of the letter's disclosure.
"The ACT DPP has requested a public inquiry in relation to this matter," he said.
"As such it would be inappropriate to provide any further comment in relation to any aspects surrounding this matter, including commentary about the letter from the ACT DPP.
"ACT Policing will continue to work cooperatively with the office of DPP to ensure the safety and security of the Canberra community."
