The widow and three daughters of a slain Toronto police officer are demanding changes to the parole system after hearing the killer of Const. Michael Sweet has been granted unescorted prison passes.

"There needs to be definitive, clear and precise rules to govern the parole board's actions," said Jennifer Sweet at an emotional news conference held Wednesday at the Toronto Police Association's offices.

On March 16, the National Parole Board turned down Craig Munro's request for day parole, but allowed to leave prison for short periods on what are called unescorted temporary absences.

The family did make representations at that hearing.

Michael Sweet died after being wounded during a botched tavern robbery by Munro in the late hours March 14, 1980. Munro needed money to pay for the fine imposed by the court on a weapons charge.

Sweet -- whose daughters were one, four and six years old at the time -- begged Munro to get him medical help. Munro refused as he felt he would be hurt by police for having shot an officer.

By the time police stormed the bar and arrested Craig Munro and his brother Jamie, it was too late:  Sweet had died of his injuries.

Munro told a parole hearing he was drunk and high and "not thinking straight." He also claimed that he didn't know the extent of Sweet's wounds.

Tim Danson, lawyer for the Sweet family, said his clients want more transparency around the Sweet case.

"The murder of a police officer is a very public act. There's nothing private about it," he said, adding it's a crime against society as a whole.

The arrest and trial process was public, but some of the parole process remains opaque, he said.

"Mr. Munro should not be able to assert a privacy interest on his prison and parole records when seeking a public remedy," Danson said, who has filed an Access to Information request for Munro's records.

Munro won't consent to their release, which is why the family wants the laws changed, he said.

"For too long, the Corrections Service of Canada and the National Parole Board have dispensed with justice at the expense of secrecy," Danson said, adding the public has a right to know the basis of the latest decision in the Munro case.

He noted that in 2009, a parole board panel wouldn't allow Munro out of prison, so he wondered what had changed in the intervening year.

Meanwhile, the pain of the Sweet family's loss continues on.

"Once again, we are sharing our feelings about Craig Munro: The man that tortured, held hostage and murdered our father, Michael Sweet," said Nicole Sweet.

Her dad dedicated this life to protecting people against criminals and murderers. "He should not be forgotten in all of this," she said.

Kim Sweet said the death of her father left her with a life filled with "pain, sadness and a huge sense of loss."

Craig Munro sentenced her father to death, she said.

With a report from CTV Toronto's John Musselman