Cincinnati Enquirer | Amber Hunt
When an Arizona man was arrested last year and charged in a 1997 Ohio rape, it wasn’t his own DNA that had triggered his arrest. It was his father’s.
The pending case against Samuel W. Legg III illustrates just how far technology has evolved when it comes to cold cases: Legg’s DNA was nowhere in the federal database known as CODIS, but scientists nowadays can zero in on single chromosomes.
“A little-known genetic fact is that every man has the same Y chromosome as his dad,” Ohio Attorney General Dave Yost said. “The Y chromosome, except for mutations, gets passed down generation to generation and stays the same.”
So investigators conducted what’s called a YSTR test to isolate that specific chromosome and ran that through CODIS. It found a match, helping police to narrow their search through old shoe-leather detective work by figuring out which male relative with the shared chromosome was in Ohio at the time of the crime.
After that, investigators flew to Arizona where Legg lived, got a warrant to obtain a sample of his DNA and, as Yost said, “Bam. We got a hit.”
Legg, a former truck driver, has pleaded not guilty to the charges. Investigators say his DNA has also tied him to at least three unsolved slayings. Steve Irwin, the attorney general’s spokesman, said more charges are expected.