The chilling night of September 9, 1910, marked a turning point in American legal history. When Thomas Jennings embarked on a housebreaking spree in Chicago’s Morgan Park neighborhood, leaving his fingerprints on a freshly painted porch railing, he unwittingly set the stage for People v. Jennings, a landmark case that established the admissibility of fingerprint evidence in the United States. This case, centered around the murder of Clarence Hiller, would forever alter the landscape of criminal investigations and forensic science.
Jennings, recently released from Joliet prison, targeted homes with the intent of sexual assault. His path of crime led him to the Hiller residence, where he entered the bedroom of Hiller’s 15-year-old daughter. Clarence Hiller confronted Jennings, and a violent struggle ensued, culminating in Hiller’s death by gunshot. The ensuing arrest of Jennings marked the beginning of a legal battle that would test the boundaries of forensic science and shape the future of criminal justice.
While eyewitness testimony, focusing on bloodstains and a torn shirt, played a role in the trial, the crux of the prosecution’s case rested on the novel concept of fingerprint analysis. Police meticulously removed the porch railing, capturing photographs and enlarging them for jury examination. These images were compared to Jennings’s prison fingerprint records. Despite fingerprint analysis being a nascent field, experts testified, employing terminology still used today: whorls, loops, and arches. The four expert witnesses included two Chicago police officers versed in fingerprinting, an inspector from the dominion police in Ottawa, Canada, and a Scotland Yard-trained U.S. government investigator. Their collective expertise lent weight to the prosecution’s argument, with all four concurring that the prints on the railing belonged to Jennings.
The court delivered a guilty verdict, sentencing Jennings to death. The subsequent appeal to the Illinois Supreme Court in People v. Jennings, 252 Ill. 534 (1911), challenged the very foundation of the conviction, arguing that fingerprint evidence lacked admissibility under common law and existing statutes.
Chief Justice Orrin Carter, in his opinion, acknowledged the unprecedented nature of the case, stating that there was no prior legal precedent in the United States. However, he drew upon scientific authorities to establish the reliability of fingerprint analysis, citing its established use in Great Britain. His conclusion was decisive: fingerprint identification possessed a scientific basis, justifying its admission in court. Furthermore, Justice Carter emphasized the cumulative weight of the evidence: the fingerprints, consistent eyewitness accounts of Jennings’s appearance, the matching bullets from Jennings’s gun, and the identical sand type found in the girl’s bed and Jennings’s shoes. While each piece of evidence individually might not have been conclusive, their combined force justified the jury’s verdict. Thomas Jennings was executed by hanging on February 16, 1912.
The Jennings case set a legal precedent, with all state courts adopting its reasoning by the late 1920s. Fingerprint evidence became a cornerstone of criminal investigations, seemingly irrefutable. However, the 21st century witnessed a growing skepticism regarding the infallibility of fingerprint identification. Experts began to acknowledge the challenges posed by incomplete or smudged prints at crime scenes, impacting the conclusiveness of matches. The case of Brandon Mayfield stands as a stark example. Mayfield’s arrest in Oregon for the 2004 Madrid train bombing was based on a supposed “100 percent” fingerprint match. Subsequent review by Spanish authorities revealed the prints were similar but not identical, leading to Mayfield’s release and highlighting the potential for errors in fingerprint analysis.
The legacy of People v. Jennings is complex. While it pioneered the use of a groundbreaking forensic technique, it also underscores the ongoing evolution of forensic science and the need for continuous scrutiny of its methods. The case serves as a potent reminder that scientific advancements, while invaluable, must be applied with caution and subjected to rigorous validation to ensure justice is served.
