DNA Recovery from Blood and Seminal Fluid Stains Exposed to Sodium Hypochlorite (Bleach)

Physical and sexual violence remains among the most prevalent crimes in contemporary society, with women and children comprising the majority of victims. In such cases, biological evidence—such as blood, semen, and saliva—plays a critical role in the investigation and resolution of criminal incidents. However, this evidence may be compromised, either unintentionally due to environmental exposure or intentionally by the perpetrator or victim, with the aim of concealing the crime. This study investigates the potential for DNA recovery from blood and semen stains that have been deliberately exposed to diluted sodium hypochlorite (bleach), a common household chemical used in attempts to destroy forensic evidence. Biological stains were deposited on various fabric types and subsequently subjected to washing with bleach and detergent at 90°C. The samples were then examined using ultraviolet (UV) light and luminol for preliminary detection, followed by DNA isolation and quantification procedures. The findings demonstrate that DNA recovery is possible even after exposure to bleach, thereby affirming the viability of forensic analysis under compromised conditions. This study underscores the potential for retrieving genetic material in scenarios where biological evidence has been subjected to intentional destruction, thereby contributing valuable insights to forensic science and criminal investigations.