Nanoparticles, a new tool to deter crime? The detection of fingermarks at a crime scene or on evidence related with a criminal affair constitutes one of the main tasks of the investigators. Fingerprints, due to their uniqueness and invariability in time, remain a key element of an identification process (being for suspects or victims). The main difficulty resides in the fact that, most of the time, fingermarks are not visible through naked eye due to their chemical composition and the small amount of material that is left on the scene. There are said to be latent and their detection requires the application of specific techniques (optical or chemical). If numerous efficient techniques currently exist, there is a continuing quest for developing new techniques or reagents with an enhanced sensitivity towards secretions and with an increased efficiency. This article gives an outline about some currently performed researches based on the use of functionalized nanoparticles to detect latent fingermarks.