An East Bay attorney has been charged with bank fraud in what federal prosecutors called the biggest criminal fraud scheme in the history of California’s Eastern District.

A federal grand jury on Oct. 5 returned a 23-count indictment against Ari J. Lauer of Lafayette for his alleged role in a $912 million conspiracy involving the purported sales and leases of mobile generators, according to documents unsealed Tuesday following Lauer’s arrest. Lauer, a solo practitioner with an office in Walnut Creek, served as outside counsel for the generator company DC Solar.