The earliest version of Tender Is the Night was based on a sensational murder case known as the Ellingson Matricide. Fitzgerald mentions the case in a letter written from Juan-les-Pins, in late April 1926, to his literary agent Harold Ober. Fitzgerald is discussing his plans for the novel that he has under way:

Matthew J. Bruccoli, writing in 1963, identified the case as the Ellingson Matricide (Bruccoli, Composition 18). Two newspaper stories about the crime were reprinted in 2003 in a volume of documentary materials about Tender Is the Night (Bruccoli and Anderson 18–23). No one, however, has investigated the case or explained why it might have attracted Fitzgerald's attention. In this essay I shall do so.

When the Ellingson Matricide occurred in January 1925, Fitzgerald was living at the Hôtel des Princes in Rome, revising the galleys of The Great Gatsby. He was anxious to follow that novel with another that was as good or better; the Ellingson case must have looked like promising material. His plan, which he developed in Paris that spring and summer, was to write a novel of matricide in which the protagonist, a young film technician named Francis Melarky, would be introduced into the company of a group of sophisticated American expatriates living in post-war France. Melarky was to have a history of violence and recklessness. He was to come to the Riviera while touring Europe with his mother, a fortyish woman who was attempting to reform him and keep him away from bad influences, including drink, which had triggered previous incidents of temper. Francis was to become involved with the expatriates, his mother was to disapprove, and he was to murder her in a fit of anger brought on by her meddling in his affairs.