OTTAWA -- In a ruling that sought to define when a kidnapping begins and ends, the Supreme Court of Canada on Thursday threw out the appeal of one of Graham McMynn's abductors.

The Supreme Court agreed with the B.C. Court of Appeal that a trial judge erred when he convicted Sam Tuan Vu of unlawful confinement rather than the far more serious charge of kidnapping.

Vu was among five men charged in 2006 after McMynn, the son of a wealthy Vancouver businessman, was grabbed at gunpoint from his car and held for eight days before he was rescued by police.

The court heard Vu bought a tarp and duct tape four days before McMynn's rescue, and threatened to kill him if a ransom was not paid.

However, the trial judge concluded that Vu could not be convicted of kidnapping since he was not involved when McMynn was first snatched from his car or moved between houses in British Columbia's Lower Mainland.

Vu was acquitted of the kidnapping charge and instead convicted of the lesser crime of unlawful confinement.

But the B.C. Appeal Court overturned the acquittal.

The appeal court judges decided it was clear Vu was involved in holding McMynn against his will and knew full well he'd been kidnapped, making him a party to the kidnapping and guilty of that offence.

The Supreme Court agreed in a unanimous 7-0 decision.

"This case illustrated why it would be incongruous to view the worst part of Mr. McMynn's ordeal (his eight days in captivity) as a separate and less serious offence than the ordeal he underwent in the few minutes it took for his captors to apprehend and remove him from his usual surroundings," Justice Michael Moldaver wrote in the ruling.

"But, as I have mentioned before, just because the offence was complete in law at the moment of the taking does not mean that it was also complete in fact. Mr. McMynn's unlawful confinement following the taking continued for the next eight days.

"The kidnapping came to an end when he was set free by the police. Put differently, Mr. McMynn's status as a victim of a kidnapping did not change during his eight days of captivity."

Vu was sentenced to eight years, but the appeal court has ordered a new sentencing hearing because kidnapping carries a maximum sentence of life in prison -- far greater than the 10-year maximum for unlawful confinement.