When diplomat Carmelo Soria doesn't come home from work in July 1976 his wife, Laura, fears the worst. Augusto Pinochet has been in power in Chile for almost three years and the disappearances of his political opponents have become hard to ignore.

The Spaniard's body is found, floating in a Santiago canal, two days later. The police say he'd had a car accident, but his widow is convinced he'd been kidnapped, tortured, and murdered.

When, 20 years later, she meets a Spanish lawyer building a complaint against Pinochet, the legal case against the former dictator finds a powerful weapon.

The Arrest is presented by Philippe Sands.

Philippe Sands is the author of '38 Londres Street: On Impunity, Pinochet in England and a Nazi in Patagonia'.