Dossier on Dumetrius is a 1951 Australian radio serial by Lindsay Hardy. It was hugely popular and was adapted into a book and a film. There were also several sequels.
The lead role was played by Bruce Stewart who became an important writer.
Major Keen of MI5 tracks down the criminal Dumetrius.
Hardy adapted the serial into a 1953 novel Requiem for a Redhead. This was filmed in England as Assignment Redhead (1956).
The series was very popular. There were four sequels, with Stewart reprising his role in the first two: