Persistence of bloodstains on natural and synthetic clothes at different temperatures using hand-wash and machine-wash with or without detergent

Abstract

Blood is one of the most significant biological shreds of evidence that helps in investigations. Bloodstains on fabrics can provide important information for the reconstruction of the crime scene. The clothes in the crime scenes are sometimes destroyed and washed by the malefactor using some detergents. This results in complete or partial degradation of bloodstains.  The impact of detergent, temperature and duration of washing clothes stained with blood on different natural and synthetic fabrics was investigated in this study. A separate batch of fabrics was allowed to wash with simple tap water to detect and compare the retention of blood. The effect of machine and hand-washing was also observed. Luminol and KM was employed as presumptive tests while the Takayama crystal test was used as a confirmatory test for the detection of blood. Findings suggested that the employment of both a detergent and 50^oC temperature is more efficient in removing a significant amount of blood as compared to washing only with tap water. In natural fibres, such as cotton, lawn and khaddar retained blood in machine washing without detergent under all temperatures. In synthetic fibres, such as velvet and chiffon, blood was detectable until washed under 50^oC with a detergent.
The fabrics obtained from the crime scene which have been washed under 50^oC with a detergent may not give positive results for bloodstains with conventionally used methods. Moreover, bloodstains not visible with naked eye can still give positive results with conventionally used testing procedures