In 1988, Houstonians Rusty Hardin and Dr. Tom Caskey – famed experts in their respective fields of law and genetics – did not know one another. Soon their worlds would collide in a moment that not only made history in Texas, but established an effective way to use DNA as evidence in criminal court proceedings.
Hardin, assistant district attorney for Harris County at the time, prosecuted the first DNA case in Houston in 1988. Caskey, then head of the molecular genetics program at Baylor College of Medicine, was his expert witness and the developer of a DNA identification technique that soon became the gold standard for criminal cases across the United States.
Hardin and Caskey, now close friends and neighbors, reflected on this case and its impact in a special lecture event Aug. 12 at Baylor College of Medicine. Organized by the Houston Forensic Science Center, the lecture event was held in recognition of the Second Annual National Forensic Week (Aug. 10 – 16).
During the lecture, Hardin recounted the events in his investigation that led him to find Caskey. The case in the spotlight focused on a man who raped and often killed elderly women. Though Hardin and his team had a suspect, the lack of hard evidence put them in a tough spot as they prepared for trial.
Jim Yarbrough, one of the investigators with the Houston Police Department, also in attendance that night, read in a magazine article about an English geneticist who used DNA as evidence to solve a crime.
At this time, no government DNA labs existed in the United States, so Yarbrough sent the suspect and victim’s DNA samples off to two of the only known commercial labs in the U.S. The labs confirmed what the team suspected, and the DNA evidence held up in court.
But Hardin needed an expert witness to explain this to the jury, to which the geneticist from England said “one of the best experts you will ever find is already in Houston.”
That expert was Caskey.
At the Aug. 12 event, Caskey discussed his first experience as an expert witness.
He recalled that he took on the difficult questions from the jury, and Hardin ultimately won the case – the first case in Texas to use DNA as evidence. But it also jumpstarted Caskey’s interest in forensic science.
Caskey was already conducting research in the identification of genes linked to human diseases, such as Fragile X syndrome. But with his knowledge in genetics was able to identify short segments of DNA – called short tandem repeats or STRs – that can be used to decipher DNA from person to person.
“This technology has been accepted worldwide as a standard for forensic analysis,” said Caskey, who would be asked time and time again to serve as an expert witness.
He eventually patented the technology. All money from the patents goes to support the Medical Scientist Training Program at Baylor. “I was sick of getting the question from defense attorneys about how I benefitted financially from this technology.”
Caskey recognized the currents students in the program at the lecture event.
The technology was also used to identify casualties of the first Gulf War in the early 1990s. The studies were conducted in Caskey’s lab at Baylor. Dr. Dan Garner, an established leader in building and improving forensic laboratories in both government and commercial environments, and current president and CEO of the Houston Forensic Science Center, helped Caskey’s team obtain the Department of Defense funding to conduct the studies.
“We completed 34 cases working through the night in a single day,” said Caskey. “This was the first validation of the technology now accepted worldwide.”