In April 1984, a young British DNA scientist, Dr Helena Greenwood was sexually assaulted in her San Francisco cottage. A year later she was brutally murdered. The alleged rapist, Paul Frediani, was the only suspect, but police and forensic experts failed to link him to the crime. The case was filed "unsolved".
After a spell in prison for the sexual assault, Frediani began to rebuild his life - with a job as a financial analyst, two children, and apparently nothing to link him to the murder - and he was confident his prison days were securely behind him.
Scientists, meanwhile, were busy exploring the mysteries of DNA and solving the riddle of human identity. By 1999 the possibilities of forensic DNA had advanced, and the Helena Greenwood murder case was reopened . . .
This is the true story of a murderer and his victim. It is the history of a science overlaid with human drama, and of a human tragedy inextricably entwined with science. It is about two lives, made and destroyed by a tiny molecule and by each other.