The method studied in this paper is developing latent fingerprints based on ruthenium tetroxide (RuO4) method. Ruthenium tetroxide fuming promptly react with various organic compound, particularly oils or fats contained in sebaceous secretions in latent print and producing brownish black or black ruthenium dioxide (RuO2).
Ruthnium Tetroxide is yellow, volatile crystails (melting point; 25.5°C, boiling point; 100.8°C) at room temperature.
Conventional methods using RuO4 have been almost impractical because it is very difficult to handle by its strong oxidizability. Additionally because of the two liquid method, it is not only troublesome to produce RuO4 fumes immediately before developing latent fingerprints, but also is difficult to produce necessary ammounts of RuO4 fumes.
In this method, these problems were resolved by utilizing a saturated hydrocarbon halogenid solution of RuO4