The U.S. Federal Bureau of Investigation is failing to disclose details of emails and meetings it held with prominent former Dechert lawyers despite facing a subpoena to do so, the victim of an alleged hacking campaign has said.

Aviation businessman Farhad Azima filed a motion in a Texan court which cited a recent deposition with the FBI agent Paul Zukas, in which he accuses the Big Law firm of using the FBI for ‘improper purposes’.