10/24/2014 06:56 EDT | Updated 12/24/2014 05:59 EST

Calgary man who killed parents not criminally responsible due to mental problem

CALGARY - A judge has ruled a Calgary man who admitted to killing his mother and stepfather was not criminally responsible because of a mental disorder.

Derek Puffer, who is 40, was charged with second-degree murder in the deaths of Billy Powers and his wife Donna-Lee.

The couple were found in their home stabbed to death in July 2013.

The defence contends that Puffer was suffering from severe schizophrenia and was in a psychotic state when he took a kitchen knife, went to his parents’ room naked and repeatedly stabbed them.

During the trial Puffer admitted to the crime, and testified that he was in a trance-like state when he heard voices telling him to kill them.

The judge's decision means Puffer will remain in psychiatric care indefinitely.

Powers retired in October 2009 after almost 50 years in the sports broadcasting and communications business.

He worked mainly in radio and was also media co-ordinator for a time for the CFL Calgary Stampeders.

Puffer was found mentally fit to stand trial last October. (CHQR)