A woman walks past the Supreme Court of Canada building. (Tom Hanson/Canadian Press)

Jury duty is considered one of the most important duties a citizen can perform and a cornerstone of democratic society.

But recently disclosed actions of Crown lawyers in a smattering of Ontario courtrooms has the legal community questioning the way in which prospective jurors make the cut.

It has been revealed that prosecutors in Windsor, Thunder Bay and Barrie were accessing information through police about potential jurors to screen them in their favour.

Notes beside potential jurors' names detailed such information as young offender convictions, charges without convictions and pardons.

Now the question has arisen: how common is this practice?

"The extent to which the police share privately information with the Crown about jurors is something that the rest of the legal profession is unfamiliar with," said David Paciocco, a University of Ottawa law professor and co-author of the book Jury Selection in Criminal Trials.

"This case has really brought forward an important question that many of us have not bothered to stop and think about."

Invasion of privacy, unfair advantage

The troubles with Crown lawyers vetting potential jurors by using police information are two-fold: it constitutes an invasion of their privacy and gives an unfair advantage to the prosecution.

"It's never OK for the police to share information with the prosecution but not the defence in our system, save in rare exceptional circumstances that clearly don't apply here," said Paciocco.

In Canada, police background checks are conducted to determine whether an individual is exempt from jury duty due to such factors as a criminal conviction.

Not all convictions warrant an exemption. Each province and territory has different rules for jury selection and exemptions for convictions are based on the type of offence in some places and the time served in others, typically prison terms of two years or more.

But in the Ontario cases, sweeping police background checks were conducted that allowed access to such information as neighbour complaints, mental health information and minor traffic infractions.

U.S.-style screening

Intensive questioning of prospective jurors is not uncommon in the United States, where information about even lifestyle and behaviour are sought.

But in Canada, defence and Crown counsel can only access basic information about potential jurors such as age, occupation and criminal records.

"The purpose behind the selection of a jury isn't intended to allow for psychological analysis or behaviour analysis to be done on the jurors. It's to try to empanel an impartial jury," Paciocco says of the Canadian system.

Frank Addario, president of the Criminal Lawyers' Association, says the Crown has long resisted the push toward U.S.-style jury vetting, while defence lawyers were open to the idea of accessing more information about potential jurors.

"So it's one of those awkward ironies in life that now it appears that while publicly the Crown was resisting it, certain Crowns were actually pursuing additional information," said Addario.

Potential to derail cases

Defence lawyers are calling for Ontario Attorney General Chris Bentley to get to the bottom of it all, saying only he can compel Crown lawyers to reveal whether they've screened jurors in the past.

Bentley has called the acts "unacceptable" and his office has asked all 54 Ontario Crown offices about how jurors were selected in the past.

The juror-screening cases have raised questions about whether clearer rules are needed to govern information sharing between Crown and defence counsel, as well as how jurors are selected.

Though it's unclear whether a court of appeal would consider the issue serious enough to overturn a conviction, the scandal has already disrupted cases currently in the system.

In Windsor, Ontario Superior Justice Bruce Thomas found the selection process "offensive" enough to declare a mistrial in a first-degree murder trial after two months of hearing evidence.

As for whether old cases could be reopened, Paciocco cautions that it's "not inconceivable, but it's highly unlikely."