Dodgy diamonds, missing millions - and the victims failed by justice. It starts with a phone call. Cynthia Tuck, a retired nurse and widow in her 80's, is charmed by a man offering her the chance to help put her grandchildren through university. All it would take is a small initial investment. Fast forward three years and Mrs Tuck has lost her entire life savings - hundreds of thousands of pounds. Three years on, in 2019, her fight for justice has hit a dead end. No charges. No trial. Everyone involved still at large. What went wrong? And why is the system failing millions of fraud victims like Cynthia Tuck? Reporter: Dan Whitworth Producer: Simon Maybin Editor: Hugh Levinson