Joshua Boyle's lawyers and the Crown agreed today to downgrade one of the sexual assault charges the former hostage faces, acknowledging there's not enough evidence to convict him on the charge as it stands.

Boyle is on trial for 19 charges — including assault with a weapon, sexual assault and forcible confinement against his estranged wife Caitlan Coleman — related to actions he's accused of committing in late 2017 after he and Coleman were freed following nearly six years as captives of Taliban-linked extremists in Afghanistan. Boyle, 35, has pleaded not guilty to the charges.

The Crown today conceded there's insufficient evidence for the trial judge to convict Boyle on a charge of sexual assault with a weapon (ropes). The prosecution confirmed in court it will proceed with a simple sexual assault charge instead.

Meanwhile, the defence and Crown spent Monday arguing over whether there was enough evidence to proceed with separate charges involving sexual assault with ropes and an accusation of public mischief.

Defence attorney Lawrence Greenspon reminded the judge that during Coleman's testimony about an alleged assault that occurred on November 27, 2017, she made several comments that raised doubts about the accuracy of her recall. Citing transcripts, Greenspon told the court Coleman suggested she was unsure if she or Boyle removed her clothes before her then-husband allegedly tied her up and had sex with her.

Crown counsel Jason Neubauer defended Coleman's credibility and accused the defence of cherry-picking Coleman's testimony.

Boyle's lawyers are asking the court to toss out another charge — that he misled police into thinking his wife was missing and suicidal when she left the couple's Ottawa home on the night of December 30, 2017. Greenspon said Coleman herself had acknowledged suicidal thoughts and a history of self-harm, suggesting it was reasonable to expect Boyle would call the police out of concern for his wife's mental state.

"All of that is critical to what is in the mind of Joshua Boyle when he picks up the phone and calls the police," Greenspon said. The Crown countered by saying that a history of self-harm doesn't equate to suicide.

The trial judge said he would give his decision on whether the charges can stand on Wednesday. Following that, the defence is expected to say whether Boyle will take the stand in his own defence.