The former head of the Northern Territory Police, John McRoberts, could find out as soon as Thursday whether a jury has found him guilty of attempting to pervert the court of justice.
An NT Supreme Court jury comprising six men and six women will continue deliberating for a second day to decide McRoberts's fate.
The lengthy trial began 38 days ago.
McRoberts, 59, has pleaded not guilty on a charge that he intended 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.
The jury retired on Wednesday after Justice Dean Mildren finished summing up.
The Crown case against McRoberts was that he was so conflicted he should have disclosed his relationship with her,
He instead tried to prevent police executing a search warrant on her business Latitude Travel, it is alleged, so text messages between the pair would not be found.
Some of those intimate messages were read out in court, including one from October 2014 to McRoberts on his birthday, saying "Im thinking of you. Adore you".
McRoberts knew at the time she was being investigated and several weeks laer she was arrested.
However McRoberts did nothing illegal, according to his lawyers, said Justice Mildren.
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.
Rather than frustrating the investigation, he was rightly involved in an inquiry involving many other travel agents, he said.