Former hostage Joshua Boyle told a self-serving lie in likening his wife's tendency to strip off her clothes to the naked protests of Russian dissenters who settled in western Canada, a federal prosecutor said Wednesday.

Crown attorney Jason Neubauer said Boyle slipped the fabrication into a false narrative to defend himself against charges of assaulting wife Caitlan Coleman after the pair were freed from overseas captivity at the hands of Taliban-linked extremists.

Neubauer also accused Boyle, 36, of making up an entire conversation from the night Coleman fled their Ottawa apartment and complained to police he had struck her on several occasions.

Boyle has pleaded not guilty to offences against Coleman including assault, sexual assault and unlawful confinement in the period of October to December 2017.

After being freed, the couple settled in Ottawa with the three children Coleman bore while a hostage. Boyle has testified the circumstances were only temporary because he intended to divorce Coleman once the children had adjusted to life in Canada.

He has described his wife as unstable, violent and prone to fits.

'Simply untrue'

Boyle told the court that Coleman would often disrobe when agitated, and that he had joked with her about behaving like a Doukhobor, a sect whose members sometimes protested in the nude.

Under cross-examination this week, Coleman appeared to have no idea who the Doukhobors were and denied taking off her clothes when distressed.

Boyle's story was "simply untrue" and just one example of his attempts to fashion his own, more favourable version of events, Neubauer said Wednesday during closing arguments at the assault trial.

The prosecution has portrayed Boyle as a controlling figure who belittled, punished and assaulted Coleman for his own ends.

Boyle's lawyers, meanwhile, have painted Coleman's testimony as the fuzzy recollections of an unreliable woman with serious emotional problems.

Caitlin Coleman has denied that she stripped naked when she was distressed. (Sean Kilpatrick/Canadian Press)

Closing arguments continue Thursday

Lawyer Lawrence Greenspon charged this week that Coleman fled the night of Dec. 30, 2017, and accused Boyle of assault as part of her long-desired plan to win sole custody of their children and make a new life in the United States, where she was raised.

Coleman's mother Lynda was visiting Ottawa from Pennsylvania that winter night, and Boyle drove her back to a hotel after dinner.

Boyle says he told his mother-in-law that she and her husband Jim needed to play a bigger role in Caitlan's life, and spoke of his plan to begin easing out of the marriage by taking separate vacations.

Under cross-examination, Lynda Coleman denied Boyle said any such thing.

Rather, she recalled it as a strange conversation because she tried to be positive by complimenting Boyle on his cooking, only to be shocked when he snapped that he was fed up with backbiting.

Of the "two very different accounts" of the same car ride, Lynda Coleman's should be believed because she is a credible witness, Neubauer said. Boyle's version, on the other hand, is "simply a lie" that feeds his narrative.

Crown co-counsel Meaghan Cunningham argued Wednesday that Caitlan Coleman is also a credible witness whose testimony during the trial has been "confirmed and supported" by other witnesses and documentation. Her evidence shows that Boyle's testimony "can't be accepted," Cunningham said.

Cunningham plans to continue with concluding statements Thursday, then Boyle's lawyers will have an opportunity to reply.