In part: the starting point of Demons is a real crime, the murder of the student Ivan Ivanov in Moscow, on November 21, 1869, by a secret revolutionary group led by Sergei Nechaev. But the novel is not reportage.
The press linked Nechaev's name to the crime only on December 29. Dostoevsky set aside the project of The Life of a Great Sinner to write, first as an anti-nihilist pamphlet, the novel that would become this one. He returned to Petersburg in July 1871, with the trial of the case under way and the first two parts already published. In the book, the murder of Shatov by the quintet, in the park, echoes Ivanov's, and a participant in the real group wrote in 1926 that Nechaev needed the crime to bind the group more firmly with blood, the same aim that Stavrogin, laughing, attributes to whoever wants to tie a circle.
The biographer Joseph Frank marks the limit: it is clear that the novel is not confined to the real, rather insignificant dimensions of the Nechaev case. It enlarges the case, as myth, into a dramatization of the tactics and aims of Nechaevism on a far greater scale.
The characters are not portraits. Stavrogin was born from a secondary figure, the "prince," who grew until he absorbed the theme of the great sinner; and Stepan Trofimovich, the satirical portrait of the generation of the 1840s, is assembled with ironic displacements drawn from the historian Granovsky.