DNA has transformed the field of forensic sciences, yet ever since its first use in a criminal investigation in 1987, the evidence has proven only as reliable as those doing the testing.
In that first case, DNA evidence aided in the conviction of Colin Pitchfork for a double rape and murder in Narborough, England. Using blood samples of the town's residents, the crime lab originally ruled out Pitchfork, who had asked a coworker to submit a blood sample for him. By happenstance, someone overheard Pitchfork's friend talking about the switch. Pitchfork eventually confessed to his crime, and DNA testing proved his guilt.1
Almost 20 years later, the quality of DNA testing has improved, but problems are still evident. Lab mistakes that have sent the innocent to prison as well as freed the guilty have prompted law-enforcement experts to call for standardization and accreditation. Standardization is particularly important, they say, in ...
