The Supreme Court of Canada has restored the conviction of an Alberta man for possession of child pornography in a case about the burden of proof for circumstantial evidence.

Oswald Villaroman took his laptop to a Calgary computer shop for repairs in December 2009, and a service technician contacted the police after discovering child pornography downloaded through a file-sharing program.

A judge convicted Villaroman of child pornography possession following a prosecution based on circumstantial evidence such as the fact that he owned the computer, which had only one user account labelled with his name.

The Alberta Court of Appeal overturned the conviction last year, ruling the trial judge had erred by excluding other possibilities as to how the pornography ended up on his computer.

The Supreme Court disagreed with the appeal judgment Friday, saying the trial judge did not make a mistake in how to apply the law.

The Crown had argued that requiring prosecutors to disprove all other possible conclusions concerning the presence of pornography would increase the burden of proof to an impossible degree.