False Positive: When forensic science fails [Full version]

On the morning of November 3, 1984, a man reported a gruesome discovery in Milwaukee: the body of 63-year-old Ione Cychosz, found beaten to death and possibly raped. The victim, known for her kindness and hobbies, was last seen alive after a night at the bingo games. The investigation faced significant challenges due to the lack of eyewitnesses, confession, or motive, and the absence of DNA profiling and security cameras. The only clue was a bite mark on the victim's body, which led to the involvement of forensic dental specialist Dr. L. Thomas Johnson. His analysis pointed to a suspect with an abnormality in an upper tooth, setting the stage for a police investigation that would focus on a young man named Robert Lee Stinson.

The narrative delves into the world of forensic odontology, specifically the controversial practice of bite-mark analysis. Dr. L.T. Johnson, a forensic odontologist, played a pivotal role in identifying victims and suspects through dental evidence. The field's development was largely independent of traditional scientific research institutions, leading to subjective assessments and a lack of established accuracy. The case of Robert Lee Stinson exemplified the challenges, as bite-mark evidence led to his arrest despite the absence of a scientific foundation for the technique's reliability. The legal system's reliance on precedent rather than scientific validity is highlighted, raising questions about the integrity of forensic evidence in the courtroom.

Robert Lee Stinson's trial underscored the US judicial system's adversarial nature, where the truth is supposed to emerge from opposing arguments. However, Stinson faced an uphill battle with bite-mark evidence presented as fact by experts, despite the field's questionable reliability. The judge's decision to admit this evidence and the prosecution's effective use of the experts' testimony led to Stinson's conviction for first-degree murder. The lack of a defense expert to counter the prosecution's claims and the absence of error rate studies for bite-mark analysis contributed to a miscarriage of justice that would have lasting repercussions.

After years of imprisonment, Robert Lee Stinson sought help from the Innocence Project, leading to a reevaluation of the bite-mark evidence and the introduction of DNA testing. The review by independent forensic odontologists revealed errors in the original testimony against Stinson, effectively excluding him as the source of the bite marks. Concurrently, the advent of DNA as a forensic tool promised a more reliable and quantifiable method of evidence, contrasting with the subjective nature of pattern-matching disciplines like bite-mark analysis. The potential of DNA to provide statistical probabilities of a match was a significant advancement in the quest for justice.

The case of Robert Lee Stinson became a precedent for bite-mark evidence in Wisconsin, despite the field's lack of scientific backing. The Daubert ruling's impact on forensic science was discussed, highlighting the need for judges to assess the validity of expert testimony but also the tendency to defer to cross-examination and contrary evidence. The challenges faced by public defenders in countering unreliable scientific evidence and the jury's reliance on expert testimony underscored the systemic issues within the justice system. The long-term effects of wrongful convictions and the emotional toll on the exonerated were poignantly captured in Stinson's story.

Robert Lee Stinson's wrongful conviction was eventually overturned following DNA testing that definitively excluded him as the perpetrator. His release in 2009 was a significant moment, but it also highlighted the flaws in the forensic science community and the judicial system. The National Academy of Sciences' report on the deficiencies in forensic science disciplines and the need for more rigorous scientific research was a call to action that was met with resistance. The case underscored the importance of continuous validation of forensic methods and the need for a permanent infrastructure to ensure the accuracy and reliability of evidence presented in court.

The story concludes with the resolution of the crime, years after Stinson's wrongful conviction. DNA from the victim's clothing, which had been preserved for decades, was finally analyzed and yielded a match to Moses Price Jr., who confessed to the crime. His confession and the DNA evidence brought closure to the case, but it also served as a stark reminder of the potential for error in the criminal justice system and the irreversible impact of wrongful convictions on the lives of the accused and their families.