Human identification from washed blood stains

Abstract

Background Among the physical evidence, bloodstain is one of the most common biological pieces of evidence at the crime scene, especially in violent crimes. Bloodstains are frequently seen at the crime scene and can be easily detected due to their color and structure. Because blood and bloodstains can potentially be evidence of a crime, offenders often tend to clean or wash them to get rid of relevant evidence. Some researchers think that washed bloodstains cannot obtain enough quality DNA for DNA profiling. However, some studies have shown that bloodstains on a piece of fabric can be used for DNA profiling even after washing. This study, it is aimed to determine whether a sufficient amount of DNA can be obtained for DNA profiling used for forensic purposes from blood-stained nylon and cotton fabrics washed at different temperatures such as 40 °C, 60 °C and 90 °C. Results In this study, bloodstains were created on cotton and nylon fabrics in a representative crime scene. After washing with laundry detergent at 40 °C, 60 °C and 90 °C was performed, studies were conducted in order to make bloodstains visible and obtain DNA for genetic profiling. The result is that more DNA is lost due to easy exposure to external factors in the non-absorbent nylon fabric type compared to the absorbent cotton fabric. Moreover, the rates of obtaining DNA from bloodstains on different types of fabrics washed at several temperatures are shown in this study. Conclusions It was determined that while a sufficient amount of DNA for the forensic genetic profiling can be obtained from cotton and nylon fabrics washed at 40 and 60 °C, a sufficient amount could not be obtained from the ones washed at 90 °C. And that shows even if bloodstained fabrics are washed at 60 °C, the fabrics still can be considered as physical evidence of the crime and can be associated with the scene, perpetrator and victim triangle.

Nucleic Acids Persistence—Benefits and Limitations in Forensic Genetics

“…Visualization of blood stains after washing can also be difficult [ 158 , 159 ]. Kulstein and Wiegand [ 160 ] confirmed, however, that despite washing blood-stained clothes at 40 °C and 60 °C, it is possible to obtain a full STR profile from the sampled material [ 161 ]. Obtaining a high-quality DNA profile was also confirmed for fabrics washed at 90 °C by Alice et al [ 152 ].…”

“…Obtaining a high-quality DNA profile was also confirmed for fabrics washed at 90 °C by Alice et al [ 152 ]. However, the results of Ünsal et al [ 161 ] contradicted the results, as they reported obtaining a complete genetic profile only from fabrics washed at 40 °C and 60 °C [ 161 ].…”

“…It was confirmed that RNA, including blood-specific miRNA, was still detectable in professionally cleaned barrels of a weapon after a touchdown shot, despite the lack of DNA presence [ 162 ]. Also, mRNA markers were detectable after washing fabrics at 40 °C, while at 60 °C, such an analysis was impossible, but eventually, the amount of genetic material collected for analysis may differ depending on the washing machine and the detergents used during washing [ 161 ].…”

Blood & blood stains in criminal investigation: A forensic perspective

“…In certain poisoning cases, the cause of death may be established from the chemical analysis of the blood. 4,5 Time since death may be estimated from the biochemical and enzyme changes in the blood. However, we must take care because false criminal charges may be brought by using animals or other blood-like substances.…”

DNA Analysis of Blood Stains on Clothing Post-Crime: A Literature Review

“…In recent years, advancements in technology have elevated the significance of DNA profiles as crucial evidence in criminal investigations, offering individualization capabilities. Consequently, the analysis of biological materials derived from crime scenes has gained heightened importance, and efforts to enhance this analysis are ongoing (Ünsal Sapan, Erdoğan and Atasoy, 2021).…”