At a hearing in Kitchener, the Crown is seeking dangerous offender status for Renee Acoby, a woman who has been committing crimes while behind bars since 2000.

That status could see Acoby in jail indefinitely. She is currently serving 18 years for crimes committed while incarcerated, on top of her initial three and a half year sentence.

Crown prosecutor Mark Poland says the crown will call evidence from a forensic psychiatrist who has assessed Acoby and from Corrections Canada regarding her conduct while she's been in the fedral penitentiary system.

The dangerous offender designation is highly unusual for female inmates.

Acoby pleaded guilty to two hostage-taking charges after an incident in 2005, when she and another inmate took two female staff members hostage at Kitchener's Grand Valley Institution for Women.

During that incident a nurse and a counsellor were tied to chairs, threatened with homemade knives or "shanks" and threatened with being burned by cigarettes. They were also reportedly forced to take anti-psychotic drugs during the three and half hour ordeal.

There have been additional forcible confinement incidents at prisons in Saskatchewan, Alberta, Quebec and Nova Scotia.

With files from The Canadian Press.