CALGARY -- An Alberta court reserved its decision Thursday morning in the appeal of Matthew de Grood.

De Grood — who was found not criminally responsible for killing five people at a 2014 house party in Calgary — filed the appeal in September after the Alberta Review Board revoked some of his privileges, having determined he continues to pose a significant threat to the safety of the public.

One of those privileges was the ability to access a group home in Edmonton.

De Grood's lawyer, Allan Fay, argued on Thursday that the decision not to allow him to stay at a group home was based on "speculation," and "what ifs", rather than information presented by his treatment team, and the review board came to an "unreasonable conclusion."

Wearing a blue golf shirt and face mask, de Grood did not speak during the hour-long hearing —which was held online due to ongoing health restrictions — but did indicate to the court he could hear the proceedings.

Crown lawyer Matthew Griener argued the board's decision was reasonable and the concern centred around whether de Grood would continue taking his medication properly.

Griener also mentioned a June 2019 episode, while de Grood was transitioning from an oral medication to an injectable one, where he experienced some deterioration over a period of weeks.

Fay countered that any decrease in mental health for de Grood wouldn't be sudden but would happen over a period of weeks or months, and would be observable to his treatment team.

De Grood has been medication-compliant to address his schizophrenia since his admission but his treatment team does not know how he would react to the transition to a group home.

The Calgarian had been charged with first-degree murder for the deaths of  Zackariah Rathwell, Jordan Segura, Kaitlin Perras, Josh Hunter and Lawrence Hong at a house party in northwest Calgary on April 15, 2014 but was found not criminally responsible in May 2016 due to a mental disorder.