The man accused of murdering aid worker Margaret Hassan is believed to have gone missing just before his retrial.
Ali Lutfi Jassar was given a life sentence at Baghdad's Central Criminal Court last June for his part in her abduction and murder and for attempting to blackmail her relatives.
He was due to appear in court for retrial tomorrow.
But Deirdre Manchanda, Mrs Hassan's sister, said last night she had been told that Jassar went missing from the prison facility in Iraq where he was being held.
Mrs Manchanda explained: ‘The Assistant Director General of the prison has confirmed that he cannot locate him.
‘Our lawyer in Baghdad expressed his concerns sometime ago about ALJ's non-appearance at any of the Appeal Hearings.’
Mrs Hassan, 59, the director of humanitarian group Care International in Iraq, was taken hostage on her way to work in Baghdad in October 2004 and shot dead almost a month later.
She was one of the highest-profile figures to fall victim to the wave of kidnappings which swept Iraq after the 2003 US-led invasion.
Mrs Hassan was born in Dublin and had joint British, Iraqi and Irish nationality.
She was married to an Iraqi and had lived in Iraq for 30 years.
A British Foreign Office spokeswoman said: ‘We stand by to provide consular assistance for Margaret Hassan's family, and want justice to be done for this dreadful crime committed against someone who dedicated her life to helping all Iraqis.’