Chemical enhancement of washed aged bloodstain on porous materials using leucocrystal violet

摘要

Blood is an important physical clue material encountered in the cases involving physical violence like murders, assaults, rapes, abortion etc. The examination of bloodstains is of immense value in reconstruction of the scene of crime and linking criminal or the victim with the scene of crime. As criminals now often attempt to clean up the crime scene and it is not known through which conditions the bloodstain has undergone before analysis. The main aim for this study is to investigate the use of leucocrystal violet to develop faint bloodstains from porous materials which will be washed with a commonly available cleaning product. Keeping this aspect in view, bloodstains have been examined after exposure to leucocrystal violet and Luminol (for comparison purpose) in order to assess their effect on the detect ability of serological markers as in blood grouping analysis. This study shows that leucocrystal violet has no destructive effect of samples as well as on elution method for the detection of blood group antigens. However, luminol did show an adverse effect on subsequent blood analysis. Thus, it is concluded that luminol has the most adverse effect on the ABO blood grouping. Based on four cloth matrices that were subjected to chemical enhancements, cotton showed the best chemical enhancement result cumulatively. This is due to chemical composition of cotton that allows chemical reactions to occur. In conclusion, positive identification in case of cloth materials that have been washed with bleaching agent and enhanced with Luminol is less accurate and less reliable to compare with samples treated with Leucocrysal violet in the same condition