The "motives" of authorities involved in the Parliament House rape case will be placed under the microscope after the ACT government finalised the terms of reference for an independent inquiry.
Chief Minister Andrew Barr and Attorney-General Shane Rattenbury revealed the scope of the high-profile probe on Wednesday, when they also confirmed it would be led by retired Queensland judge Walter Sofronoff KC.
Mr Sofronoff, a former Queensland Court of Appeal president, will look at whether police officers and the ACT Director of Public Prosecutions breached, or failed to act in accordance with, their duties.
If he finds they did, the respected legal figure will examine "the reasons and motives for their actions".
The government also revealed Mr Sofronoff would inquire into the circumstances surrounding the release of a letter that made the public aware of tensions between police and prosecutors, and which cast a shadow over the integrity of the territory's criminal justice agencies.
Mr Barr and Mr Rattenbury first announced the board of inquiry in December, when the Attorney-General said the territory government was "deeply concerned" by explosive allegations of misconduct.
Calls for an inquiry had been mounting at the time, following the release, under freedom of information laws, of a letter written by ACT Director of Public Prosecutions Shane Drumgold SC.
In the November 2022 letter to ACT chief police officer Neil Gaughan, who has privately told his officers he was not consulted before its public release, Mr Drumgold made the extraordinary claim investigators had unsuccessfully pressured him not to prosecute Bruce Lehrmann.
Mr Drumgold alleged police then aligned themselves with the defence of Mr Lehrmann, who has always denied raping Brittany Higgins at Parliament House when the pair were Liberal Party staffers in 2019.
After Mr Lehrmann's ACT Supreme Court trial was aborted last October because of juror misconduct, Mr Drumgold dropped the case as a result of fears the impact a retrial would have on Ms Higgins' health.
The government has previously said the inquiry would examine the ACT's legal framework for dealing with juror misconduct.
It will also look at whether the support ACT Victims of Crime Commissioner Heidi Yates provided Ms Higgins during the trial was appropriate, given the presumption of innocence afforded to Mr Lehrmann.
Mr Barr, who anticipates receiving the inquiry's findings in the first half of 2023, said on Wednesday the allegations and complaints made about the ACT's criminal justice agencies were serious.
"Mr Sofronoff is a highly regarded legal expert with experience leading sensitive inquiries throughout his career," he said.
"He was also Queensland's Solicitor-General for almost 10 years. I am confident that Mr Sofronoff will deliver a thorough and respectful independent inquiry."
Mr Rattenbury said the inquiry was established to ensure the territory's framework for progressing criminal investigations and prosecutions was "robust, fair and respects the rights of those involved".
"It is important to remember that this will not be a retrial of the case," the Attorney-General said.
"It will focus on whether the criminal justice officials involved performed their duties with appropriate rigour, impartiality, and independence."
ACT Opposition Leader Elizabeth Lee has previously criticised the territory government for not outlining an intention to have the inquiry examine claims of "political interference" in the case.
However, the inclusion of "motives" in the terms of reference ensures such allegations can be examined if police or Mr Drumgold are found to have engaged in misconduct.
