In May 2008, Walter Swift was exonerated after serving 26 years in prison for a rape he did not commit. Mr. Swift’s case, like many where an innocent person is convicted, didn’t have just a single error. One problem was with the identification that not even the investigating detective believed. Another problem was that forensic evidence that should have cleared Mr. Swift was withheld.
Before DNA became the standard forensic test for identifying the source of bodily fluids at crime scenes, forensic analysts tested for blood type antigens. Depending on the antigens detected, the source of the bodily fluid could be identified as type A, B, AB, or O. If the test failed to show the presence of any antigens, the bodily fluid would be identified as coming from a “non-secretor” to denote an individual who doesn’t secrete enough antigens to be detected by the forensic test. Approximately 20% of the population is found to be “non-secretors.” (For more details on this testing procedure, see Kathleen E. Boorman et al, Blood Group Serology (1988); Ivor Dunsford & Christopher Bowley, Techniques in Blood Grouping (1967); David Harley, Medico-Legal Blood Group Determination (1944); Leon N. Sussman, Blood Grouping Tests (1968).)
Although Mr. Swift’s blood type did not match the blood type found in fluids at the scene, he was tested by forensic analysts and found to be a non-secretor. (It was withheld that prior testing found that Mr. Swift WAS a secretor, and therefore he could not be a match for the bodily fluids found at the scene.) Mr. Swift’s purported non-secretor status allowed the prosecution to explain the absence of Mr. Swift’s antigens in the bodily fluids found at the crime scene. Recent retesting of Mr. Swift found that he was in fact a secretor, and because this meant Mr. Swift could not have left the bodily fluids found at the scene, the court vacated his conviction.
I recently had the pleasure of speaking with Mr. Swift about his case. While in prison Mr. Swift was required to attend group counseling. During the course of this counseling, the inmates talked about their cases and Mr. Swift was startled to learn that 11 out of 15 (73%) members of the group were convicted as non-secretors! It is worth noting that while secretor status is genetically controlled, without laboratory testing an individual would have no way of knowing or acting based on their secretor status. Given this fact, the variation between the percentages of non-secretors in this group (73%) from the population (20%) is startling. This variation can this be explained by both inadvertent mistakes and intentional malfeasance in the testing, but regardless of the source of the error, this variation suggests a problem with the forensic science used against accused rapists (among others) in Michigan.
It is worth noting that Mr. Swift is not the only individual where recent retesting has proven that an individual convicted as a non-secretor is in fact a secretor. After spending 23 years in prison, recent retesting has proven that Karl Vinson is a secretor, contrary to the testing showing him to be a non-secretor that was used to secure his conviction. A motion to set aside Mr. Vinson’s conviction is currently pending in Wayne County Circuit Court. Mr. Swift and Mr. Vinson are both notable for never giving up the search for justice. How many others were not so persistent and remain in prison for crimes they did not commit?
When errors were identified from the Detroit Police Department Firearms Lab, District Attorney Kym Worthy started an immediate audit of trial convictions and guilty pleas that relied upon the crime lab’s findings. The same must now be done for those convicted as “non-secretors” within the state of Michigan. The prosecutors fought hard in search of justice for the victims of street crimes, and it is time for them to search for justice for those who have been victimized by the justice system itself.