Two analytics firms have attributed the incident to a North Korean hacking unit called TraderTraitor.

The alleged scheme used stolen identities to claim US student aid, with Kenyans among those charged.

BBC business reporter Archana Shukla explains more about what is suspected to be the largest hack in history.

In her first interview since the incident, Joanna Wietrzyk told the BBC she takes responsibility for it but did not deserve such a severe backlash.