In April 2012, Greg Craig was in the capital of Ukraine, fuming over money and threatening to leave the country before his work for its government had even begun.

Craig, then a partner at the law firm Skadden, Arps, Slate, Meagher & Flom, had traveled to Kiev after being approached about preparing an independent report on the Ukrainian government’s case against Yulia Tymoshenko, a former prime minister whose prosecution was widely criticized as politically motivated. On the trip he met with Victor Pinchuk, the Ukrainian oligarch bankrolling the project, who discussed making a $1.5 million transfer.