The case of a Crown prosecutor found liable for maliciously prosecuting several Saskatchewan people for child sexual abuse went before the Supreme Court of Canada on Friday.

Crown prosecutor Matt Miazga appealed to the country's top court to overturn a lower court's finding that he improperly proceeded with a notorious case of abuse that was built on wildly false allegations.

Richard Klassen was one of 12 people who were falsely accused in the early 1990s of horrific acts of child sexual abuse in what media once called the scandal of the century.

The allegations originated from two girls and their brother who were, for a time, placed in a foster home with Klassen's brother and sister-in-law beginning in February 1987. Years later the public learned it was all made up.

Led by Richard Klassen, a house painter with a Grade 7 education who turned out to be a quick study on the law, the family sued for malicious prosecution. They won five years ago, 13 years after their collective nightmare began.

Klassen calmly conducted his own case in a Queen's Bench courtroom in Saskatoon, and argued Miazga proceeded with his case even though he knew the allegations were false.

On Friday, Miazga's lawyer Michael Tochor told the Supreme Court his client had reasonable and probable grounds to prosecute the case.

Miazga did not believe all of the bizarre allegations, but he was convinced the children were abused by one or more people, Tochor said.

Klassen told the high court that Miazga was malicious, and accused him of lying about why the charges were dropped. At the time, Miazga told the public it was because the children were too traumatized to testify.

'Do your job right,' Klassen says

The case is attracting the attention of provinces and public interest groups across the country.

The Saskatchewan government has been supporting Miazga's appeal. It has argued that if the malicious prosecution finding is allowed to stand, it could put a chill on the ability of Crown prosecutors to do their jobs.

However, the Canadian Civil Liberties Association says the lower court's decision should stand.

"It is the prosecutor and the people who are favouring the appeal here who are frankly trying to rewrite the law in the area," association spokesman Brad Berg said. "We will argue that that's not appropriate."

It could weaken the rights of the wrongly accused if Miazga wins his appeal, Berg said.

Klassen said outside the courtroom Friday that he didn't think upholding the decision would stop anyone from doing their jobs.

"This isn't putting a chill on anything," he said. "Do your job right."

The court reserved its decision. It's expected the decision could take months.