10/25/2017 14:43 EDT | Updated 10/28/2017 13:24 EDT

Parole Board of Canada denies Edmonton hostage taker's appeal for release

ABBOTSFORD, B.C. — A man who took nine people hostage at gunpoint in Edmonton has lost a Parole Board of Canada appeal for release from custody.

Patrick Clayton is serving an 11-year sentence for hostage-taking, pointing a firearm and possession of a weapon for a dangerous purpose in relation to a 2009 incident at the Workers' Compensation Board office.

Clayton was granted day parole in November 2015 but that was revoked this May after he was found to be deceitful and manipulative, that he breached his curfew and was exhibiting impulsivity and poor decision making.

After being returned to prison, the board says Clayton admitted to using prescription and street drugs to mitigate mental health issues and was also engaging in a relationship with a sex worker.

Clayton claimed on appeal that he was not previously given an option to attend a treatment centre and also wants job training.

But in a decision released to the media Wednesday, the board's appeal division says Clayton had attended two previous substance treatment programs and he continued to use and abuse drugs.

The division's documents say it supports the decision to revoke Clayton's parole because his deteriorating behaviour took place "behind the scenes" without the knowledge of his case management team and his problem behaviour continued despite significant interventions.

"The Board found that, despite ongoing interventions, you were unable to put into practice the skills to minimize behaviours which in the past had put the community at significant risk," says the Oct. 13 decision.