Supreme Court overturns rape conviction over flawed DNA evidence handling

The Supreme Court on May 29 overturned a rape conviction, ruling that the lower court erred in accepting DNA evidence without verifying whether the sample had been tampered with during a two-year period.

The case involved a defendant accused of raping a victim in the back seat of his vehicle. While the first instance court acquitted the defendant due to insufficient evidence, the appellate court later convicted him based on new DNA analysis submitted by prosecutors detecting the defendant's Y-chromosome DNA on the inner surface of slacks the victim wore.

The Supreme Court noted critical gaps in how this physical evidence was handled. The victim had kept the pants for more than two years between the alleged crime and their submission to investigators, with no testimony or judicial inquiry regarding whether the victim or any third party might have manipulated the garment. Furthermore, DNA from several unidentified men was also found on the clothing.

The justices determined that it could not be objectively guaranteed that the pants remained free from artificial alteration. The court stated that scientific evidence only holds significant binding power for fact-finding when the authenticity of the material is secured throughout collection, storage, and analysis.

When such evidence serves as the sole or primary basis for a conviction, courts must exercise extreme caution to avoid blind reliance on its scientific nature. The prosecution bore the burden of proving that the identity of the material was maintained and that no contamination occurred, yet the lower court accepted the forensic report without examining these prerequisites.