By John A. Lupton, Supreme Court Historic Preservation Commission

When Thomas Jennings broke into several houses in Chicago’s Morgan Park neighborhood on the night of September 9, 1910, he was unaware one of the houses had a freshly painted porch. After grabbing ahold of the porch railing, Jennings left four fingerprints, which were later used in court as evidence to convict him of the murder of Clarence Hiller — the first case of its kind in the United States.

Jennings had recently been released from the state prison in Joliet. He broke into the houses with the intent to sexually assault women. When he reached the Hiller house, he entered the bedroom of the 15-year-old daughter. Clarence Hiller, the father, confronted Jennings, and after a scuffle, Jennings shot and killed Hiller. The police arrested Jennings.

At the trial, eyewitnesses were able to identify Jennings because of blood stains and a ripped shirt. Much of the testimony, however, concerned Jennings’s fingerprints. After the murder, police removed the porch railing, took photographs and enlarged them for the jury to compare with the prison records of Jennings’s fingerprints. Fingerprint analysis in detective work was a fairly new field, but specialists used the same descriptors that we continue to use today: whorls, loops, and arches. Four expert witnesses in Jennings’s trial included two Chicago police officers with experience in fingerprints; an inspector from the dominion police in Ottawa, Canada; and a U.S. government investigator who was trained at Scotland Yard, which was the first police force in the world to use fingerprint analysis in detective work. All four agreed that the prints on the porch rail belonged to Jennings.

The court found Jennings guilty and sentenced him to death. Jennings appealed the case to the Illinois Supreme Court in People v. Jennings, 252 Ill. 534 (1911). One of the reasons for appeal was that fingerprint evidence was not admissible under the common law rules of evidence and there was no statute authorizing its admissibility.

In his opinion, Chief Justice Orrin Carter noted that there was no “case in which this question has been raised” and “we find no statutes or decisions touching the point in this country.” Carter cited scientific authorities showing fingerprint analysis to be reliable and noted that Great Britain had been using fingerprints as evidence. He concluded that “there is a scientific basis for the system of finger-print identification and that the courts are justified in admitting this class of evidence.” Carter added that the cumulative testimony was overwhelming: the fingerprints, the eyewitnesses agreeing on Jennings’s appearance, the bullets killing Hiller were from the gun that Jennings had on his person when arrested, and the type of sand found in the girl’s bed was the same as in Jennings shoes. “No one of these circumstances, considered alone, would be conclusive of his guilt, but when all of the facts introduced as evidence are considered together, the jury were justified” in finding Jennings guilty. Jennings was executed by hanging on February 16, 1912.

By the end of the 1920s, all state courts followed the reasoning in the Jennings case. In the 2000s, experts began to dispute the notion that fingerprint identification was foolproof. Prints at crime scenes are often incomplete or smudged, making positive matches more difficult and less conclusive. One prominent example is the Brandon Mayfield case. Mayfield was arrested in Oregon for the 2004 bombing of a Madrid train because his fingerprint matched “100 percent” with a print found on a plastic bag at the bombing site. When the Spanish authorities reviewed the print and found that it was similar but not the same print, Mayfield was released.