jats:titleAbstract</jats:title>jats:pThis article explores the relation between suspicion and expertise in the context of activist investigations of offshore corruption. I reconstruct one investigation of alleged corruption in the Azerbaijani oil sector, conducted by a British organization called Global Witness, to explore how suspicion is learned and practised in the face of impenetrable offshore secrecy. For these detectives of global capital, suspicion is both a tool for arriving at an understanding of offshore corporate networks and an orientation that helps them overcome the limits of this understanding, allowing them to make political claims that go beyond what is strictly afforded by evidence and libel law. Extending recent anthropological scholarship that revises the disciplinary emphasis on truth and certainty as the mainstays of expert knowledge, I argue that investigative expertise provides imprecise and suspicious understandings of its objects that are useful despite, or even because of, the ambivalence and suspicion it entails.</jats:p>