The killing of Sophie Toscan du Plantier in West Cork in 1996 was one of the most infamous murders in Irish history.
Nick Foster has been piecing together her life and death for several years.
He has now written a book, Murder At Roaringwater, which claims that Ian Bailey was responsible for the murder, and that he knew Sophie – something Bailey has always denied.
Nick joined us on The Last Word to discuss the book.
