The brother of murder victim Meg Walsh – whose husband was cleared of her killing last year – has met with the justice minister to discuss new legislation overhauling the 'double jeopardy' rule that prevents people who have been acquitted to be re-tried for the same crime.

Under the Criminal Procedure Bill 2009 published three weeks ago, Dermot Ahern has proposed an end to the ban on retrying people who have been acquitted, known as the double jeopardy rule.

However, this will only apply to crimes that take place after the enactment of the legislation.

This means that should new evidence implicating John O'Brien in his wife's killing emerge, he cannot face fresh charges under the proposed new laws.

James Walsh met with Ahern three weeks ago to appeal to him to change the proposed legislation to make it retroactive, similar to the laws in Britain.

"As the law stands at the moment, if someone walks back into a garda station and admits to a crime they were cleared of in court, admits to giving the guards the run around and ridiculing the justice system, there's not a thing that can be done to this person," Walsh told the Sunday Tribune.

"I commend the justice minister for the new legislation but I believe it should be retroactive. The minister gave us a very good hearing and a lot of his time, he listened to our case. He said he believed it could be problematic to apply the law retrospectively but he's still looking at it. My legal advice is that it would not be impossible but it would be costly and would involve an amendment to the Irish constitution. The law should serve the people and not be its master."

Margaret 'Meg' Walsh (35) went missing on 1 October, 2006, after a row with her husband at their home in Ballinakill Downs, Waterford. She was found floating in a river just two weeks later.

O'Brien had caught her kissing another man, Owen Walsh, at their home after a night out; it emerged during her murder trial at the Central Criminal Court in May 2008, which heard up to 120 witness accounts. O'Brien, who admitted to beating his wife under oath, was cleared of her murder.

Three weeks ago at Waterford district court, 42-year-old O'Brien failed to secure jewellery belonging to his dead wife. Gardaí told the court that the state needs the items as part of a "live investigation" into the murder of the
35-year-old mother-of-one.