Results indicate that it is the eccrine component of the latent fingerprint that caused the fluorescence of the marks after exposure to temperatures in excess of 100 degree Centigrade with the maximum luminance observed from marks heated in the range of 160 to 180 degrees Centigrade. Findings show that fingerprints will fluoresce under excitation from violet-blue light between 350 to 469 nm with a 476 nm viewing filter, blue light between 352 to 509 nm with a 510 nm viewing filter, and green light between 473 to 548 nm with a 549 nm viewing filter. Thermal decomposition of amino acids has been previously investigated and has suggested three decomposition reaction products, of which two have the molecular structure that could account for this fluorescence, although this has not been directly investigated in this work. Sodium chloride and urea are also accountable for the fluorescence in the mark, but other eccrine sweat constituents could also contribute to the fluorescence. Figures and references