Sam Bankman-Fried’s criminal conviction over the collapse of FTX should be vacated in part because the cryptocurrency exchange’s former lawyers at Sullivan & Cromwell “did an enormous amount of investigative work for the prosecution”, attorneys for the former billionaire have argued.

In a brief filed with the US Court of Appeals for the Second Circuit on Friday, Bankman-Fried’s counsel claimed he was denied a fair trial by “federal prosecutors eager for quick headlines” who co-opted former colleagues at the elite New York firm into gathering evidence for the government.

S&C, which advised FTX before providing counsel to the cryptocurrency exchange’s bankruptcy, “worked hand-in-glove with the prosecutors to charge and imprison Bankman-Fried, in ways that far exceeded normal ‘co-operation’,” they wrote.