Novel hydrophobic silica based particles have been developed to visualize latent fingerprints. Development of latent fingerprints generally involves either use of a dusting agent that adheres to the sticky material deposited on the surface following contact, or a chemical developer that produces the visual coloration due to chemical interaction of the applied developer with chemicals commonly found within the deposit materials on the surface. A direct route to the synthesis of equivalent nanoparticles, which is simpler and can be applied to production of a variety of colored and fluorescent agents, and to agents that have colored and magnetizable particles embedded within them. How such particles can be used in suspension as developing agents for latent finger prints and in an agglomerated form such as dusting agents is described, as well as examples provided. A range of stable silica nanoparticles have been produced which have embedded within them a variety of dyes and sub-particles. The composition of the particles has been designed to maximize both hydrophobic and ionic interactions between a variety of color and fluorescent reporter molecules, and the silicate backbone within the particles. The resulting doped particles retain the incorporated dyes with high affinity. In addition, a variety of sub-particles have also been invented to introduce colored or magnetizable hydrophobic particles. The particles can be harvested as nanoparticles or microparticles. The former are applied to latent fingerprints as an aqueous suspension, and the latter as a dusting agent using brushes or a magnetic wand. The resulting prints have good definition; examples of the prints produced using these agents are provided. Figures, references