Nova Scotia's opposition parties say an independent public inquiry is needed into how authorities handled the case of an accused sex offender whose long-standing legal saga was thrown out of Canada's highest court.

On Monday, the Supreme Court of Canada rejected the Crown's appeal of a lower court decision that quashed all 17 sex offence convictions against Ernest Fenwick MacIntosh, a Cape Breton businessman now living in Dartmouth.

The convictions came almost 15 years after allegations surfaced that he sexually abused boys in the 1970s. The Nova Scotia Court of Appeal — in dismissing those convictions — argued MacIntosh was not brought to trial in a timely manner.

The Supreme Court of Canada agreed.

Michel Samson, the Liberal justice critic, said an inquiry is needed to get an explanation on why it took so long to get the case to court. He first asked the province to start a review when the Nova Scotia Court of Appeal threw out the convictions in 2011.

"There obviously were major problems with the federal side of this, with the extradition process. Major problems on our provincial side in the length of time it took once Mr. MacIntosh was back in the country before charges were brought forward," Samon said Monday.

"Someone has to explain what went wrong here. More importantly, let's make sure that this never happens again."

Justice Minister Ross Landry said the Nova Scotia Public Prosecution Service has promised him a full report by mid May, but that wasn't good enough for members of the opposition.

Allan MacMaster, the Progressive Conservative justice critic, said prosecutors should report what they know immediately.

"For the sake of the victims that should be something they know the answers to already, what really happened," he said.

"They should have that to the public within a week."

Long delays

MacIntosh's legal saga began in 1995, when the RCMP received complaints from two men who said MacIntosh abused them back in the 1970s when they were boys.

Over the years, more complainants emerged and the list of charges grew to more than 40 counts of sexual abuse involving nine people.

Even though police knew exactly where MacIntosh was living in India, he wasn't extradited until late 2007; more than 11 years after the first complaints to police. Once back in Nova Scotia, it took almost three years for the trial.

During the first trial, he was convicted of 13 counts of gross indecency and indecent assault and sentenced to four years in prison. In a second trial, MacIntosh was convicted on another four counts and sentenced to another 18 months in jail.

MacIntosh's lawyers successfully appealed all the convictions to the Nova Scotia Court of Appeal, arguing the 11 years it took to extradite him from India, plus the three-year delay in getting to trial once he was back in Nova Scotia, violated his charter rights to be tried within a reasonable time period.