Politicians on both the left and the right have criticised the appointment of foreign nationals as deputy prosecutors in Switzerland.
An Italian, a Dutch and a German hold the posts, justice ministry spokesman Philippe Piatti confirmed to Sunday's NZZ am Sonntag newspaper.
Green Party parliamentarian Daniel Vischer said the practice was "sickening" and Christa Markwalder of the centre-right Radical Party called it "problematic".
Deputy prosecutors hold virtually the same powers as federal prosecutors, including ordering detentions and house searches, and seizing assets.
The Italian and Dutch deputy prosecutors already served under the tenure of Chrstoph Blocher, the former justice minister from the rightwing Swiss People's Party.
The German national previously held a position in canton St Gallen after Blocher's replacement, Eveline Widmer-Schlumpf, issued an exemption permit. He will take up a post in canton Zurich this month.