Dustin Paxton's alleged victim might have been systematically conditioned to the point that he was in a state of "frozen fright," a U.S. captivity expert has testified at a Calgary torture trial.

Dr. Kris Mohandie, a psychologist and expert on human captivity who was consulted at the O.J. Simpson trial, was called by the Crown Wednesday to explain why the alleged victim might have remained with Paxton, despite apparently having had opportunities to leave.

Paxton, 31, is being tried on charges including the forcible confinement, sexual assault and aggravated assault of his one-time business partner and roommate, who cannot be named because of a publication ban.

"The person is operating on a level which is moment to moment, they've been broke down so much that all they're worried about is the immediate timeframe, 'What can I do to lessen the likelihood of assault,'" he said.

Mohandie told the court that victims of such crimes are usually targeted, and then conditioned over time — through verbal abuse, monitoring and degradation — to submit to physical abuse and torture.

"It fuels their unwillingness, it fuels their sense of powerlessness, it fuels their perception that there's no way out," he said.

The forensic psychologist said the process can leave a victim in a state of "frozen fright," unable to take action or leave the situation.

Trial to hear more from captivity expert 

Paxton's alleged victim testified in court that he performed sex acts on Paxton because he would have done anything to stop the beatings.

"They come to see their survival, their perceived survival, in the immediate term is tied into their ability to keep the captor pleased or less displeased," said Mohandie.

Earlier on Wednesday, Court of Queen's Bench Justice Sheilah Martin ruled that Mohandie's testimony would be relevant and necessary. Paxton's defence team had tried to have him disallowed, arguing that he was not properly qualified.

The judge-alone trial began on Sept. 27. While it was scheduled to last five weeks, the trial has been adjourned until next Tuesday when the defence will continue its cross-examination of Mohandie via video link from Los Angeles.

Paxton's lawyer told the court earlier that he would need one hour to cross-examine Mohandie, but after 90 minutes of questioning the psychologist told the court he needs another hour.

Mohandie could not find a later flight to Los Angeles Wednesday and had to leave the courthouse at 5 p.m. MT.

The judge said she is "most-distressed that the trial has been delayed."

Mohandie is the last witness to be called by the Crown.