Evaluating DNA report as evidence

Context:

Recently, in various cases, the Supreme Court raised concerns that “the collection and sealing of the samples sent for examination are not free from suspicion.” 

Careful sampling is a must:

• The first responder on the scene of crime needs to ensure that the biological sample is dried under room temperature and sealed in a paper.
• The sample should be free from any contamination due to humic acid, which is a primary constituent of the soil.
• Touching areas where DNA may exist, and talking, sneezing and coughing over evidence must be avoided. 
• No other human contact should be allowed, and stained articles must be packed separately.
• The investigating officer (IO) must ensure that the properly sealed samples reach the forensic science laboratory (FSL) in the stipulated time period, maintaining proper chain of custody.
• The Union Home Ministry had provided a sizeable number of sexual assault evidence collection kits containing blood collection cards and EDTA vials in 2020 to all the States so that the biological samples are collected and preserved in the best possible manner for DNA analysis. The States need to continue with this good practice.
• All stakeholders of the criminal justice system need to be sensitized about the techniques of DNA analysis.

Not mentioning the Random Match Probability:

• The random occurrence ratio or random match probability (RMP) is referred to as the frequency of the particular DNA profile in a population. 
• A small RMP value means the profile is rare in the population and vice versa. 
• The Central FSL, Directorate of Forensic Sciences, released a Working Procedures Manual Forensic DNA Testing in 2019, which prescribes the procedure for calculating RMP for automated Short Tandem Repeats (STRs). 
• Therefore, there is no justifiable reason for a DNA expert not to mention RMP in its report.

Conclusion:

• DNA technology has evolved over the years. 
• As the evidence of DNA matching in criminal cases, particularly those based on circumstantial evidence, acquires great importance, some standard guidelines need to be laid down by the Court for admitting the DNA expert’s report as credible evidence.                                                                                                                                                                 

News Source: The Hindu