Prosecutor worried police could 'derail' Lehrmann case

The chief prosecutor in former Liberal staffer Bruce Lehrmann's rape trial says his objectivity was not affected during the case despite his concerns over the conduct of some police investigators.

ACT Director of Public Prosecutions Shane Drumgold provided a third day of evidence to an independent inquiry into how the territory's justice system handled rape allegations made by Mr Lehrmann's ex-colleague Brittany Higgins.

Mr Drumgold told the inquiry a decision by police to conduct a second interview with Ms Higgins was "irregular" in a sexual assault case.  

"I held concerns because a subsequent interview would be traumatic to a complainant (and) my position was that if there was an inconsistency it should be left to the defence," he said.

"The (police) evidence-in-chief interview looked like a cross examination. It looked like a defence cross-examination."

Mr Drumgold said he held separate concerns about the motivations of some police officers communicating with Mr Lehrmann's defence team.

"My concern was (police) going to great lengths to feed inaccurate information, inaccurate assessment of information, in the hope of derailing the case," he said.

His concern was shared by a deputy commissioner in the ACT Police, who warned her officers against speaking with Mr Lehrmann's lawyers.

Mr Drumgold has previously given evidence that police investigating the allegations tried to convince him not to charge Mr Lehrmann. 

But asked whether this assessment of police affected his ability to be objective in the case, he said no.

"I was leading evidence. I lead evidence in the same way in this trial as every other trial," he said.

The ACT government established the inquiry after accusations by police and prosecutors about each other's conduct during the case.

Former Queensland solicitor-general Walter Sofronoff is leading the inquiry which is examining how territory police, prosecutors and a victim support service handled Ms Higgins' allegations.

Mr Lehrmann faced an ACT Supreme Court trial in October 2022 but juror misconduct meant a verdict was not reached.

Prosecutors later dropped the charge against Mr Lehrmann because of concerns about the impact a second trial would have on Ms Higgins' mental health.

Mr Lehrmann denies raping Ms Higgins in Parliament House in 2019.