The Panama Papers leak landed with a bang — 2.6 terabytes, 11.5 million internal documents, and almost 40 years of confidential client information. Deemed the largest breach in history, the disclosure implicated scores of public figures, including politicians from Vladmir Putin to the now former prime minster of Iceland, Sigmundur Davíð Gunnlaugsson.

But beneath the uncovering of corruption, tax evasion, and the dark hinterlands of the global economy, was the uncovering of yet another disclosure, one that like offshore banking is widely assumed, but usually unseen — the breach of a law firm.