The usefulness of user-generated online reviews is hampered by fake reviews, often produced by clandestinely sponsored reviewers. Detecting fake reviews is a difficult task even for laypeople, and this has also been the case for previous automatic detection ap-proaches, which have only had a limited success. Earlier studies showed that people who tell lies or write deceptive reviews tend to select words unnaturally. We propose a novel approach to detecting fake reviews by applying a topic modeling method based on Latent Dirichlet Allocation (LDA). A unique contribution of this paper is to explicate some latent aspects of fake and truthful reviews by means of