It originally focused on characters from existing detective stories across literature (The Saint, Bulldog Drummond, Fu Manchu), radio (Dick Barton) and film (Harry Lime of The Third Man fame).
From relatively early on the comic also dabbled in science fiction. Issue 14 introduced a new character, Rod Collins - Special Agent in Space; shortly after this came stories such as Kidnapped by Martians (issue 23) and Revolt on Venus (issue 35).
Issue 37, with its story "Crime Rides the Spaceways", introduced a longer-lasting spacefaring detective named Rick Random. Although the science fiction stories accounted for a surprisingly large chunk of the comic's output during this time, there was still time for more traditional detectives: Sherlock Holmes made his debut in issue 65. Around the same time the comic also introduced Inspector Chafik of the Baghdad Police and the female detective Lesley Shane; these two emerged, alongside Rick Random, as the comic's main characters.
Later, the comic begun to rely heavily on reprints of the American strip Rip Kirby, the original characters - aside from Rick Random - being sidelined in the process. Reprints of the British newspaper strip Buck Ryan also began appearing towards the end of the comic's life, along with John Steel, a character who also appeared in Thriller Picture Library.