A variety of evidence samples have been brought into the Identification section of the police for detection of latent fingerprints. Fumes of cyanoacrylate ester are generally used to detect latent fingerprints on flat surfaces, such as cutlery, in a case of murder. White fingerprint ridges fixed by the fumes are generally stained with dye powder or dye solution.
  We developed new reagents which can detect latent fingerprints the same method as using both the fumes of cyanoacrylate ester and fluorescent staining. First, polycyanoacrylate ester powder was produced from its monomer and water as an initiator. Then, 5 percent of p-dimethylaminocinnamaldehyde (DMAC) or p-dimethylaminobenzaldehyde (DMAB), each of which has volatility and fluorescence that could be excited by ultraviolet light or blue light respectively, was added to the polycyanoacrylate ester powder. The developed reagent depolymerized and yielded monomer at a lower temperature than polycyanoacrylate powder that polymerized in methanol containing 1% water. The mixed DMAC or DMAB can simultaneously stain and give fluorescence to the white fingerprint ridge. Added to that, exposing samples to acetic acid vapor for a short time has increased the fluorescence intensity and shifted excitation wavelength to a longer one such as ultraviolet to blue and blue to green.
  By use of this reagent, the fumes of cyanoacrylate ester and fluorescent staining was achieved simultaneously. The gaseous phase detections are specially recommended for evidences that are composed of material that is easily destroyed due to its physical contact with powder or liquid in the dyeing process.