Jurors who ignore judge's directions by researching the history of cases could be charged with an offence and face possible jail terms under a proposal being investigated by WA Supreme Court Chief Justice Wayne Martin.
Justice Martin said he would refer the issue to Supreme and District court judges after the third trial of Ronald Leslie Pennington was aborted this week because a juror was provided with background about the case by his partner, then shared the information with other members of the jury.
Mr Pennington is accused of killing Cariad Anderson-Slater in July 1992. The 85-year-old was convicted of manslaughter after his first trial in 2012 but his conviction was quashed on appeal and he was ordered to face a retrial.
A jury could not reach a verdict after his second trial in November and his third trial started on Tuesday. State prosecutors are reviewing the case to determine whether to pursue a fourth trial.
Justice Martin said it was a "dreadful outcome" that could have been avoided if the juror had followed the strong directions of the trial judge, Justice Michael Corboy.
Justice Martin said he had asked for a report from Justice Corboy and he would refer the issue of introducing a "juror research offence", similar to laws which operate in NSW, to his colleagues.
Justice Martin said it was conceivable that contempt laws could apply in cases where jurors disobeyed judge's directions, but a specific offence would be preferable and avoid ambiguity.
He said the consequences of jurors ignoring directions not to conduct their own investigations into cases could be serious and he would not exclude the possibility of jail term as a maximum penalty.
Justice Martin said until now, judges had been nervous about suggesting an offence because of concerns it could intimidate jurors and discourage them from reporting irregularities.
Criminal Lawyers Association of WA president Linda Black said the availability of information on the internet was a "massive problem" and access by jurors to the background of cases could not be controlled.