Agent Sunde (played by Johannes Fritz) was not Swedish, according to the manuscript. His 'true' nationality was never revealed, despite him speaking Swedish fluently. Agent Bruun (played by Jonas Larsson Grönström) referred to him as his "Danish friend" in an early scene, but that line was an improvisation by the actor during filming and later lost during editing.
Jonas L. Grönström and Johannes Fritz were actually 10 years younger than the characters that they played: Grönström's acting age was 34 years at the real age of 24 years, and Fritz's acting age was 27 years at the real age of merely 17 years.