การตรวจหารอยลายนิ้วมือแฝงบนกระดาษเปียกโดย เทคนิคออยล์เรดโอและเทคนิคการใช้สารอนุภาคขนาดเล็ก

Abstract

This research focuses on the revealing latent prints on wet papers by using Oil Red O and small particle reagent techniques. The objectives are to study the effect of immersing time and the effect of pH on the durability of latent prints. The fingerprints were deposited on the papers by researcher and then were placed in distilled water and the solutions with different pH (4, 7 and 10) for 7 days. At the different time intervals, the wet papers were taken out and examined the latent prints by using Oil Red O and small particle reagent techniques. The minutiae of latent prints on wet papers were investigated and reported as the average number of the minutiae of latent prints per fingerprint. The results showed that Oil Red O technique can be used to reveal the latent prints on wet papers in which are the fingerprints can be observed. In addition, the small particle reagent technique can be also used to reveal latent prints on wet papers but the fingerprints cannot be clearly observed. Moreover, it can be concluded that the pH of water do not affect the investigation of the latent prints on wet paper in the studying period.