Cargo of Bulgarian steamship Koningin Maria Louisa seized by British according to a letter of the German naval attaché at Istanbul dated 22 December 1939

In his letter dated Istanbul, 22 December 1939 No. 575g reported the German naval attaché to the Oberkommando der Wehrmacht Abteilung Ausland the steamships passing Istanbul. An item reported that the Bulgarian steamship Koningin Maria Louisa passed mid November loaded with 4,000 ton grain bound for Italy. She was stopped in the Dardannelles by British warships and with a prize crew brought to Malta. There was her cargo seized and unloaded. She passed again on 17 December coming empty from Malta. 

Source

Bundesarchiv. German Marineattaché for , Greece, Romania and Bulgaria 1939-1941. RM 12-II/459.