Franco Orr was convicted in 2013 and sentenced to 18 months in jail for human trafficking, illegally employing a foreign national and lying to immigration officials.
He was charged along with his wife, Oi Long Nicole Huen, who was acquitted after the couple's jury trial.
Orr appealed, and the province's top court sided with him Tuesday on one of four grounds — that the trial judge was wrong to allow the testimony of an expert witness — and ordered a new trial.
Yvon Dandurand was called by the Crown to testify about "victimology," a discipline focusing on how victims react to situations they face, and was asked a series of hypothetical questions in front of the jury.
Justice Peter Willcock, writing for the three-member B.C. Court of Appeal panel, said the jury should have never heard Dandurand's testimony because his qualifications had not been tested.
"There was insufficient evidence of the probative value of the expert's opinion to justify its admission," wrote Willcock. "There was a clear risk that its admission would be wrongly relied upon as oath-helping."
The judges dismissed Orr's other arguments that it was unreasonable for the jury to convict him while acquitting his wife, and the judge erred in instructing the jury on one of the counts.
They also dismissed Orr's claim that he suffered a "miscarriage of justice" because the jury should have heard statements made by the complainant to an officer that were inconsistent with her testimony during the trial.
Orr had been charged with bringing Leticia Sarmiento into Canada from Hong Kong on false pretences, paying her $500 a month to take care of his three children.
Sarmiento worked for 22 months before calling 911 to file a complaint.
When B.C. Supreme Court Judge Richard Goepel handed down his sentence in 2013, he said the Crown didn't prove that Sarmiento was subjected to humiliating or degrading treatment, but did prove that the man profited by paying low wages.
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