The ACT's top prosecutor feared that federal ministers may have interfered with police to try to thwart the prosecution of Bruce Lehrmann, an inquiry has heard.
Shane Drumgold's allegations that ACT detectives pressured him not to prosecute Mr Lehrmann is the main reason the ACT Board of Inquiry was established.
It is examining whether criminal justice agencies met their responsibilities in the case of Mr Lehrmann, a former Liberal Party adviser who was accused of raping Brittany Higgins in Parliament House in 2019.
Mr Lehrmann has maintained his innocence after his trial was abandoned late last year. There have been no findings against him.
On Wednesday, Mr Drumgold, who is the ACT's Director of Public Prosecutions, told the inquiry about what he suspected was behind the pressure on him from police.
"Some of the questions in my mind hypothetically were: was this at the time a government minister exerting pressure through the [Australian Federal Police] commissioner onto ACT Policing to make a matter go away?" he said.
Mr Drumgold made the remark during a discussion about the letter he sent to ACT Chief Police Officer Neil Gaughan, which sparked the inquiry.
In that letter, he asked that police have no further contact with defence or prosecution witnesses, saying he "had in mind" Liberal senators Linda Reynolds and Michaelia Cash.
"I'm looking at the circumstantial strands … enthusiastic engagement by a senator … an unprecedented passion that a number of police held that this matter shouldn't proceed," Mr Drumgold told the inquiry.
"There were just enough circumstantial strands in my mind to at least justify investigation into them."
Senator Reynolds issued a statement to media on Wednesday, rejecting any suggestion she exerted political pressure on police.
"This suggestion is baseless and without any foundation," she said.
Inquiry canvasses potential 'conspiracy' involving ministers
Mr Lehrmann and Ms Higgins worked for Senator Reynolds at the time of the alleged assault, when she was a minister in the Morrison government.
During the criminal trial last year, Senator Reynolds confirmed she had sought transcripts of the hearings from Mr Lehrmann's defence lawyers, while her partner observed the trial from the back of the court before she took the stand.
Witnesses had been told not to monitor the trial before they gave evidence.
The counsel assisting the inquiry, Erin Longbottom, asked Mr Drumgold if he believed there was "a conspiracy afoot" between police and members of the former Coalition government.
"I'd not formed a view solidly one way or another," the DPP replied.
"I thought that there [were] enough incidents to make it possible, if not probable."
Police 'aligned themselves with an acquittal'
The inquiry also probed Mr Drumgold's perception that police were engaging closely with Mr Lehrmann's lawyers.
The chair of the inquiry, Walter Sofronoff, asked what police could have shared with the defence that was not already legally disclosable.
"I'm seeing what's breaking the surface and I don't know what's happening underneath the surface," Mr Drumgold replied.
"What is breaking the surface are sufficient anomalies for me to be curious about what's happening underneath."
He said the discussions between police and the defence compounded his earlier perception, formed during initial meetings about the case, that police had "aligned themselves with an acquittal".
Ms Longbottom asked Mr Drumgold whether by the time he wrote the letter, on November 1, his perceptions had been "coloured" by what happened in the trial.
"That's possible," he replied.
Ms Longbottom then said: "What you're saying here in the letter may not be an accurate reflection of your perceptions at the time."
But Mr Drumgold rejected the notion there was a substantial difference, saying his perception of an early meeting with police was "that they were trying to snowball the prosecution".
Mr Drumgold's testimony continues.
