Douglas Garland has been named in local media reports as the man who was taken into custody Saturday for questioning in the case.
Police said the man was released from questioning Sunday, but remains a person of interest in their investigation.
Garland was, however, charged with identity theft in an unrelated case and was brought before a judge where his case was adjourned until a bail hearing Wednesday.
Investigators continue to search for clues in the disappearance of Nathan O'Brien and his grandparents — Alvin and Kathy Liknes — who were last seen June 29.
Garland has had problems with the law in the past, with a court document showing he went to prison in 2000 for making amphetamines at his parents' farm, which is just north of Calgary.