Fair Warning (Jack McEvoy #3)(34)

“Life sciences,” he said. “Is that what we older folks used to call plain old biology?”

Hammond fake-smiled back, as he did at every trial.

“Yes, it is,” he said.

“Can you describe what DNA is and what it does in layman’s terms?” Walsh asked.

“I can try,” Hammond said. “DNA is short for deoxyribonucleic acid. It is a molecule composed of two strands that twist around each other, forming a double helix that carries the genetic code of a living thing. By code I really mean instructions for the development of that organism. In human beings DNA contains all our hereditary information and therefore determines everything about us, from the color of our eyes to the function of our brains. Ninety-nine percent of the DNA in all human beings is identical. That last one percent and the myriad combinations within it is what makes each of us completely unique.”

Hammond gave the answer like a high school biology teacher. He spoke slowly and recited the information with a tone of awe. Walsh then moved on and led him quickly through the basics of his assignment to the case. This part was so routine Hammond was able to go on autopilot and glance a few times at the defendant. It was the first time he had seen him in person. Robert Earl Dykes, a fifty-nine-year-old plumber, had long been suspected of killing his ex-fiancée, Wilma Fournette, in 1990, stabbing her to death, then throwing her body down a hillside off Mulholland Drive. Now he was finally brought to justice.

He sat at the defense table in an ill-fitting suit his lawyer had given him. He had a yellow legal pad in front of him in case he came up with a genius question to pass to the lawyer next to him. But Hammond could see it was blank. There would be no question from him or his lawyer that could undo the damage Hammond would inflict. He was the Hammer and it was about to come down.

“Is this the knife that you tested for blood and DNA?” Walsh asked.

He was holding up a clear evidence bag containing an opened switchblade.

“Yes, it is,” Hammond said.

“Can you tell us how it came to you?”

“Yes, it had been sealed in evidence from the case since the original 1990 investigation. Detective Kleber reopened the case and brought it to me.”

“Why you?”

“I should have said he brought it to the DNA unit and it was assigned to me on rotation.”

“What did you do with it?”

“I opened the package and examined the knife visually for blood and then under magnification. The knife appeared to be clean but I could see that there was a spring-loaded mechanism in the handle, so I asked for a knife expert from the toolmark unit to come to the lab to disassemble the weapon.”

“Who was that?”

“Gerald Lattis.”

“And he opened the knife for you?”

“He took it apart and then I examined the spring mechanism under a lab magnifier. I saw what I believed to be a minute amount of dried blood on the coil of the spring. I then began a DNA-extraction protocol.”

Walsh walked Hammond through the science. This was the boring technical part where the danger was that the jurors’ thoughts could wander off. Walsh wanted them keenly interested in the DNA findings and asked quick, short questions that required quick, short answers.

The provenance of the knife would have already been testified to by Kleber. The knife was confiscated from Dykes when he was originally questioned in the investigation. The original detectives had it examined for blood by a lab using archaic methods and materials and were told it was clean. When Kleber decided to reopen the case at the urging of the victim’s sister, he took another look at the knife and brought it to the DNA lab.

Finally, Walsh arrived at the point where Hammond provided his findings that the DNA extracted from the minute amount of blood on the spring of the switchblade mechanism matched the DNA of the victim, Wilma Fournette.

“The DNA profile developed from the material on the knife does match the profile from the victim’s blood obtained during the autopsy,” Hammond said.

“How close is the match?” Walsh asked.

“It is a unique match. A perfect match.”

“Can you tell the jurors if there is a statistic associated with that perfect match?”

“Yes, we generate statistics based on the human population of Earth to give a weight to that match. In this case the victim was African-American. In the African-American database, the frequency of this DNA profile is one in thirteen quadrillion unrelated individuals.”

“When you say one in thirteen quadrillion, how many zeros are we talking about?”

“That would be a thirteen with fifteen zeros behind it.”

“Is there a layman’s way of explaining the significance of this frequency?”

“Yes. The current population of Planet Earth is roughly seven billion. That number is significantly eclipsed by thirteen quadrillion. That tells us there is no one else on Earth or in the last one hundred years on Earth who could have that DNA. Only the victim in this case. Only Wilma Fournette.”

Hammond stole a glance at Dykes. The killer sat unmoving, his eyes downcast and focused on the blank yellow page in front of him. It was the moment. The Hammer had come down and Dykes knew that it was over.

Hammond was pleased with the part he had played in the legal play. He was the star witness. But it also pained him to see another man go down for what Hammond did not consider to be much of a crime. He had no doubt that Dykes had done what he had to do, and his ex-fiancée had gotten what she had coming.