Xavier Justo is a retired Swiss banker and the 1MDB whistle blower. In 2011, Justo had handed a British journalist named Clare Rewcastle Brown thousands of documents, including 227,000 emails, from the servers of his former employer, PetroSaudi, which appeared to shed light on the alleged theft of hundreds of millions of dollars from a state-owned Malaysian investment fund known as 1MDB. The documents that Justo leaked have set off a chain reaction of investigations in at least half a dozen countries, and led to what Loretta Lynch, the US attorney general, described as “the largest kleptocracy case” in US history. Later that year he arrested by Thai police and flown to Bangkok. Justo was charged with an attempt to blackmail his former employer, a little-known London-based oil-services company named PetroSaudi. But behind this seemingly mundane charge lay a much bigger story.