One of two Mississauga sisters convicted four years ago of killing their mother will be let out of prison and allowed to move to a halfway house.

The woman, who cannot be identified, was granted early release so she can do university studies this fall.

The sisters were convicted in 2005 of killing their mother in 2003 by drowning her in the bathtub.

The 22-year-old who was given early release was a minor at the time of the crime.

A judge in Brampton, Ont., agreed Monday to change the conditions of her sentence.

She will go to a halfway house in Barrie, Ont., and from there she will be allowed to take online courses with the University of Waterloo where she has been awarded a $2,000 scholarship.

The woman's father was in the courtroom along with other family members to hear the ruling. 

Father 'extremely happy' with decision

He told CBC News the decision was "fantastic" and that he is "extremely happy" that he'll be able to see his daughter from time to time.

She will be allowed to take some field trips but under no circumstances will she be allowed to touch drugs or alcohol.

The Crown prosecutor in the case described the 22-year-old as a model prisoner and a straight A student.

Court documents say she has exceptional intelligence and has "earned the privilege" of early release. 

She has, according to the documents, gone through all the counselling and rehabilitation offered by the justice system. 

In April, the other sister, age 21, was denied early release from prison for a second time. The judge told her she needed more counselling before she can expect to be released.

The sisters were sentenced to the maximum 10-year sentence for first-degree murder in the deliberate and planned drowning of their alcoholic mother in the bathtub of their Mississauga townhouse. 

With files from The Canadian Press