DNA evidence was first used to solve a crime in 1986, when British police in Leicestershire, England applied geneticist Alec Jeffreys’ new DNA fingerprinting technique to a double murder investigation. The work cleared an innocent teenager who had already confessed and ultimately identified the real killer, Colin Pitchfork, who was convicted in 1988. So the answer to what year DNA was first used to solve crimes depends slightly on what you mean: 1986 for the first investigative use, 1987 for the first criminal conviction built on DNA (in Florida), and 1988 for the conviction in the original British case.
The 1984 Discovery That Made It Possible
The technique behind all of this was barely two years old when police picked it up. On the morning of September 10, 1984, Alec Jeffreys, a geneticist at the University of Leicester, produced the world’s first DNA fingerprint.1University of Leicester. DNA Fingerprinting He had been studying short, repetitive sequences scattered throughout human DNA and realized the patterns they created varied dramatically from one person to the next.2National Library of Medicine. Visible Proofs: Forensic Views of the Body – Alec Jeffreys and the Pitchfork Murder Case Comparing those patterns on a lab image let him distinguish one person’s genetic makeup from virtually anyone else’s. Jeffreys initially saw applications in paternity disputes and immigration cases. A criminal investigation was not on his list.
The 1986 Pitchfork Murders: DNA’s First Criminal Case
The case that pulled DNA into criminal justice involved two killings in villages near Leicester. In November 1983, fifteen-year-old Lynda Mann was raped and murdered. In July 1986, Dawn Ashworth, also fifteen, was killed in strikingly similar circumstances. The similarities convinced investigators that one perpetrator was responsible for both.3New England Journal of Medicine. DNA as Evidence – The Technology of Identification
Police had a suspect. A local teenager named Richard Buckland had confessed to the Ashworth murder. Investigators asked Jeffreys to confirm the confession using his new technique, and the results surprised everyone. Buckland’s DNA did not match the crime scene evidence from either killing, and the analysis also showed that one unknown person had committed both. Buckland walked free, becoming the first person ever cleared by DNA profiling.2National Library of Medicine. Visible Proofs: Forensic Views of the Body – Alec Jeffreys and the Pitchfork Murder Case
What came next was unprecedented. Police launched a voluntary DNA screening of about 5,000 men in the surrounding area. The dragnet initially failed because the real killer, Colin Pitchfork, persuaded a coworker to submit a sample in his place. When the coworker was overheard boasting about the swap, police arrested Pitchfork. His DNA matched both crime scenes, and he was convicted in 1988, the first criminal conviction secured through DNA evidence anywhere in the world.3New England Journal of Medicine. DNA as Evidence – The Technology of Identification
The First American DNA Conviction in 1987
DNA crossed the Atlantic quickly. In May 1986, a woman in Orlando, Florida was raped at knifepoint in her apartment. DNA from the crime scene matched a blood sample taken from Tommie Lee Andrews, and in November 1987 he was convicted of sexual battery and armed burglary. He was the first person in the United States convicted using DNA evidence.4CaseMine. Andrews v. State
The conviction was upheld on appeal in November 1988, when Florida’s Fifth District Court of Appeal issued what appears to have been the first appellate decision in the country addressing DNA identification evidence in a criminal case. The court noted it could find no prior appellate ruling on the subject and concluded that the trial court had properly admitted the evidence.4CaseMine. Andrews v. State
States began building infrastructure around the new technology almost immediately. In 1989, the Virginia Department of Forensic Science became the first state laboratory to create a DNA databank, initially cataloging profiles from convicted sex offenders.5Virginia Department of Forensic Science. DNA Data Bank
The First DNA Exoneration in 1989
DNA did not just put people in prison. It pulled innocent ones out. On August 14, 1989, Gary Dotson became the first person exonerated through DNA testing in the United States, after serving ten years for a rape conviction.6Office of Justice Programs. Exonerations in the United States, 1989-2003 Flawed eyewitness identification and limited biological testing had contributed to the wrongful conviction.
The most dramatic early exoneration came four years later. Kirk Bloodsworth had been convicted of the murder and sexual assault of a nine-year-old girl in Maryland and sentenced to die. DNA testing of the crime scene evidence excluded him, and he was released on June 28, 1993, becoming the first death row inmate in the United States freed by DNA. His case became a powerful argument for preserving biological evidence long after trial and for giving convicted people access to testing that did not exist when they were sentenced.
Within the span of roughly seven years, from Jeffreys’ 1984 lab discovery to Bloodsworth’s 1993 release, DNA had proven itself in both directions: identifying the guilty when confessions and eyewitnesses pointed the wrong way, and freeing the innocent when the same flawed inputs had already produced a conviction. The year DNA first solved a crime was 1986, but the shape of what the technology could do was really set over that entire opening decade.