A Superior Court judge has declared 32-year-old Renee Acoby a dangerous offender following a months-long hearing that began in September.

Acoby was involved in a series of violent incidents while behind bars, including a 2005 hostage-taking at the Grand Valley Institution for Women in Kitchener, Ont.

In that case, she and another inmate held a nurse and councillor hostage. They were burned with cigarettes, cut with shanks and had the handmade knives held to their throats.

Other forcible confinement incidents occurred at prisons in Saskatchewan, Alberta, Quebec and Nova Scotia.

During the hearing Acoby claimed she hadn't done anything violent in three years and was trying hard to control herself.

However, a psychiatrist in the case found Acoby suffered from an anti-social personality disorder and that there was a very high risk she would re-offend violently.

The prosecution also introduced photos of Acoby, describing them as sexually provocative, though Acoby disagreed with the description.

Prosecutor Mark Poland says "In this case there's no winners and there's no losers. This is really a story, at end of the day, of a life wasted and in that sense it's a tragedy all around."

The dangerous offender label is unusual for female inmates.

A study in 2002 by the Correctional Service of Canada looked at dangerous offenders and those placed on long-term supervision orders starting in 1994.

Of the 274 offenders placed under those designations in that time period, only one was female.

Acoby is currently serving an 18 year sentence for crimes committed while she was behind bars. The designation could see Acoby remain in prison indefinitely.

The defence says it will appeal the decision and believes Acoby could be safely supervised in the community.

Defence lawyer Paula Roachman adds "I'm surprised because the clear evidence in this particular case was that Renee Acoby is in no way a danger to people outside of corrections. Her concerns and all of the concerns she's had with violence have happened inside an institution."

Acoby is currently serving time at a women's prison in Edmonton, Alta. and will get her first chance to apply for parole in 2012.