Douglas Garland, accused of killing Nathan O'Brien and grandparents, appears in court

The man charged in the deaths of Calgary residents Kathy and Alvin Liknes,and the couple's five-year-old grandsonNathan O'Brien, was in court Thursday, ahead of his triple-murder trial, which is set to begin next year.

DouglasGarland was present for a voir dire hearing, a legal procedure in which the admissibility of evidence is discussed.

• Douglas Garland murder trial set for 2017 in deaths of Nathan O'Brien, grandparents
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O'Brien and his grandparents disappeared in June 2014. Their bodies have never been found.

While the motive of the killings is unclear, police have confirmed they're looking into a patent dispute and other business dealings between GarlandandAlvinLiknes.

Liknes'sson was also in a common-law relationship with Garland's sister.

All three murder victims were missing for two weeks before police laid murder charges. But a court document reveals investigators believe theydied onJune 30, the day they were reported missing by Nathan's mother.

With no bodies and likely no eyewitnesses, forensic evidence gathered at the Liknes's home, as well as the Garland property, are expected to play a prominent role in the case.

The start date for the five-week jury trial has been set forJan. 16, 2017, with jury selection taking place the week before.