As an investigative tool, DNA has been a powerful weapon in identifying or confirming who committed a crime. But the value of DNA evidence is overshadowed by regular stories of corruption, incompetence, and flawed interpretation. It’s, for this reason, I never accept the DNA results as golden for the prosecution in a contested case.
Two linked issues are driving the ongoing saga. The first came to light last summer, when an investigation found problems with how the Broward Sheriff’s Office crime laboratory was interpreting complex samples, which contain DNA from more than one person. With its accreditation threatened, the lab last July ceased reporting those complex samples and instead began sending them to outside experts.