Trial by Twitter and Facebook is against the law.

The law regarding the justice process is very clear – as soon as a person is charged with an offence, especially murder, it is illegal to publish anything about the accused that might jeopardise them getting a fair trial. They are presumed innocent until found guilty in court.

Newspapers, radio and television can't publish details of an accused's prior convictions or charges against them. They can't run any commentary on the guilt or innocence of the accused. They can't publish photos or information about the accused that may influence a witness or juror.

Break these laws and the publisher and reporter can be held in contempt of court and face stiff penalties, even jail. Everybody has the right to a fair trial, and these laws are designed to prevent witnesses or juries being influenced by what they may see in the media.

But today any individual who sets up a Facebook page, website or Twitter account is, in effect, a publisher. Just like a professional journalist, social media users are also subject to these laws.

The issue of how much social media can interfere with the justice system has exploded after a man was charged with the rape and murder of Jill Meagher in Melbourne.

The tragic case saw an understandable outpouring of grief, anger and rage on social media. The unprecedented level of abuse and rumours about the accused man prompted police to plead with people not to post anything on social media that could "endanger the accused's presumption of innocence as it had a very high potential to interfere with the administration of justice".

For three days police asked the US-based Facebook to take down several Facebook pages that contained details of the accused man's past and advocated violence against him. Even Mrs Meagher's family begged Facebook to take down the sites as it may give the defence a chance to argue he can't get a fair trial. One site had more than 44,000 likes and was still growing before Facebook finally agreed to remove the sites. But others have since appeared.

This prompted debate on whether the law was out of date as social media is unstoppable. Some asked whether the presumption jurors would be influenced by such publications was right, and perhaps it was time to trust jurors to stick to the evidence produced in court to reach a just decision.

But until then, social media users should remember they could end up in court for contempt of court or defamation.

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