Nearly 30 years on from one of the most notorious murders in modern Irish history, the investigation into the killing of Sophie Toscan du Plantier has taken a new turn. Gardaí are now seeking assistance from police forces across Europe and beyond, in an effort to identify a DNA trace found on the victim’s boot - evidence that could yet reshape understanding of a case that has long confounded authorities. Barry Roche, Southern Correspondent with the Irish Times, joins Pat to discuss.