What is the main conflict in A Coffin for Dimitrios by Eric Ambler?

Detective novelist Charles Latimer becomes fascinated with the dead villain Dimitrios and on a whim begins to investigate Dimitrios's life. His quest leads him to one of Dimitrios's former partners in the drug business, Mr. Peters, whom Dimitrios double-crossed and sent to jail. Mr. Peters reveals that Dimitrios is actually alive and convinces Latimer to help him blackmail the villain. The dangerous and witty Dimitrios, though, tracks his blackmailers down, and Latimer is lucky to escape the gun battle that kills both Peters and Dimitrios.