A jury will continue deliberating in the Supreme Court trial of former Northern Territory police commissioner John McRoberts.
The jury retired on Wednesday after Justice Dean Mildren finished summing up the trial that has been running for more than five weeks.
McRoberts, 59, has pleaded not guilty of attempting to pervert the course of justice.
He is accused of having an intent to "frustrate" or "deflect" the investigation by his own police force into numerous travel agents including his lover, Xana Kamitsis, who had been defrauding an NT government pensioner concession scheme.
Kamitsis was ultimately jailed for rorting taxpayers of $120,000.
The Crown case against McRoberts was that he was so conflicted he should have disclosed his relationship with her and removed himself from any connection to the investigation, Justice Mildren told the jury.
However, out of self-interest, he had "embarked on a course of conduct to prevent police executing a search warrant on her premises", that would have revealed their involvement through text messages.
Some of those intimate messages were read out in court including one from October 2014 on McRoberts's birthday, only weeks before Kamitsis was arrested.
"Probably the most lonely and sad birthday I can remember but shit happens," McRoberts says.
"Your birthday is so important to me. I'm thinking of you. Adore you BB xxxxxx," Kamitsis replies.
McRoberts did nothing illegal, according to his lawyers, Justice Mildren said.
He was not on trial for immorality, though both he and Kamitsis were in relationships with other people at that time, defence lawyer Tony Elliot had said.
"It was put that this was a very unusual investigation that required massive resources, had significant implications for the travel industry, the Department of Health and also had political implications as part of the big picture," Justice Mildren said.
The jury will continue deliberating on Thursday.