BRYAN – The prosecution in the KFC murder trial of Darnell Hartsfield called an expert in forensic DNA testing, who testified the fingernail found on a victim’s body was not that of a former suspect.
Texas Attorney General prosecutor Lisa Tanner asked Roby when she became involved in the KFC case and she answered she was director of the Armed Forces Institute of Pathology when they agreed to conduct DNA testing on the fingernail.
Roby said they had never performed DNA testing on nails so they had to first conduct a study to determine how to best move forward.
She said the scientists at the AFIP cut their own fingernails and drew their own blood and then worked to pull DNA from the fingernails. They then attempted to match both and found they did match. They also found a woman who had broken a nail years before and had kept it. She offered the fingernail to the study and had her blood drawn to test if it matched and again Roby said it did.
Posted Wednesday, Sept. 24, 2008 at 12:18.m. CDT
She testified she received blood and fingernails from Mankins who for years was a suspect. He was cleared by the DNA testing that Roby and her lab performed.
"That fingernail fragment could not have come from James Mankins or a maternal relative of his," she said.
She also testified the DNA found in the fingernail matched the DNA found in Mary Tyler’s known fingernails clipped during autopsy.
Roby said investigators in the KFC were "reluctant to accept the fingernail did not come from Mr. Mankins."
Prosecutors with the Texas Attorney General’s office as well as investigators believed the nail belonged to Mankins including former Texas Ranger Stuart Dowell.
The case became scientific proof that DNA could be taken from fingernails and has since been published to the forensic community and is the case cited in new criminal proceedings. Roby said scientist and attorneys call her in regards to the discoveries learned in the KFC case and her involvement in pulling DNA from a decade old fingernail.
Defense co-counsel Thad Davidson began his cross of Roby by asking if she had seven files on the case with her. Roby said she only brought one file and Davidson asked if her office had previously offered a defense team in another proceeding with all of the files. Roby said she believed that was correct. Davidson again asked Roby where the files were and she said she had not brought them with her. Davidson then asked to talk to the judge outside the presence of the jury.
During a recess Tanner gave the defense her copy of the files so they could study them before the cross examination continued.
Davidson questioned whether or not Roby and her associates in AFIP had been switched and was not Mankins’ fingernail.
"Do you know if that fear ever went away," Davidson asked.
"I don’t know the answer to your question," she answered.
Roby said by the time they received the sample, it had been through multiple labs with numerous people.
"I wouldn’t say we believed it was switched, I think we heard and were informed concerns from the attorney general’s office about the fingernail," she said. "We never had fear about what we had received."
Davidson then asked if the nail could have been Kim Miller’s fingernail instead of Mary Tyler, her mother. Miller and Billy Tyler were the ones who called police the night of the abductions to report the victims’ disappearances.
Roby said based on nuclear DNA that were performed and without testing Miller with mitochondrial DNA the answer would be unknown.
Davidson then asked if the box in the case, which allegedly has Hartsfield’s blood on it, with the blue fingerprinting ink and other resins used to construct it could change the DNA.
Roby said it could inhibit DNA but would not change it. She also said that the DNA could degrade over time, but again would not change.
Tanner then on redirect asked where the fears about the nail came from and Roby said the fears originated with the Texas Attorney General’s Office and were not fears in her lab.
Tanner asked questions about DNA and if there was anything anyone could do to change the results of DNA testing once a result had been obtained.
"DNA is DNA if I get one result it is not going to flip over to another type because of degradation or inhibitions. It is still going to be the same DNA," Roby said.