The prosecution called several forensic specialists in the trial of Marty Roe Tuesday.
Roe is accused of killing Dr. Martha Post in 2011.
They focused largely on one piece of evidence: a Bursa .38 caliber pistol. On it, one forensic biologist said she found Roe's DNA.
"The estimated frequency of this profile is one person in 770 trillion based on the relevant United States population," said Alison Tunstill, who works in the Kentucky State Police's forensics lab.
To compare, there are 315 million people in the U.S.; 7 billion in the world. Tunstill was unwilling to say whether Roe touched the gun.
"There was a red-orange staining that was present on the slide of the pistol," said Kathleen Holznagel, a former forensic biologist with KSP.
She said she was unable to do anything more comprehensive for fear of contaminating possible fingerprints.
However, when a fingerprint analyst with the state police took the stand, he said there weren't any usable prints on either the gun or its magazine.
Lawrence Bilcher, another specialist with the forensic lab, said the bullets in evidence were hollow-point.
"It's [the bullet] placed there for a specific reason is to expand the bullet up on its terminal impact and spread as much of the energy over a larger area as possible as fast as possible," he said in testimony Tuesday.
He said the microscopic markings on them, though, weren't enough to make an identification or to eliminate them from being attributed to the gun in question.
The prosecution later rested.