DNA Experts Testify At Fairbourn Trial


DNA experts were among those who took the stand today during the trial of Bradley Fairbourn.

Fairbourn, age 20, is on trial for Murder in the First Degree and Attempted Murder in the First Degree. He stands accused of killing Naisha Story and injuring Linda Natalia Arce in a knife attack at the Quality Inn in Rock Springs early on June 23, 2016.

Day three of the trial began with continued testimony from Christopher Crayton, Arce’s boyfriend. Crayton testified yesterday that he saw Fairbourn running from the scene and got into a physical altercation with him when he attempted to stop him from leaving.

Today, defense attorney Rob Oldham asked Crayton if it was possible that Arce and Story got into a fight which resulted in the stabbing. Crayton said he did not believe such an event occurred, and said Arce never said anything to him indicating that Story’s death and her own injuries resulted from an altercation between the two of them.

The Emergency Room Physician who was working at Memorial Hospital of Sweetwater County, Dr. Alicia Peterson, and the Forensic Pathologist who conducted Story’s autopsy, Dr. Michael Burson, also testified during trial today. Burson said Story died from massive blood loss and exsanguination due to stab wounds, and her manner of death was homicide.

The defense called their first witness today, DNA Expert Dr. Greg Hampikian.  He was called before the defense would normally call witnesses due to a scheduling conflict for Hampikian.

John Bunning

As an expert witness, Hampikian said he was getting paid by the defense for his testimony and work on the case with the amount capped at $10,000.

Hampikian began his testimony by presenting the jury with a PowerPoint presentation about DNA basics. Much of his testimony focused on mixtures of DNA—samples with more than one source.

“When there are mixtures, there can be disagreement among experts,” he said.

He testified that identifying those who contribute to a mixture of DNA can be incredibly difficult, and experts often come to differing conclusions with the same data.

Hampikian said new technology using Probabilistic Genotyping, such as the STRmix software used at the State Crime Lab, has helped to eliminate some of the problems when interpreting mixture DNA, but it relies on assumptions as to how many people contributed to the DNA sample.

Hampikian said he questioned the methods used in the Wyoming State Crime Lab because reference DNA samples from suspects were out at the same time as evidence samples.

“This is, in my view, an extremely sloppy practice,” said Hampikian.

He said this method could lead to cross contamination, although he was unable to say if cross contamination occurred in this case.

Jennifer Brammeier, Senior Forensic Analyst, and Christina Buettner, Forensic Scientist and DNA Technical Leader, both testified today as expert witnesses on behalf of the prosecution. Both women were receiving their regular salaries to testify as a part of their employment at the Wyoming State Crime Lab.

They both testified that methods and protocols used at the State Crime Lab are established by the FBI and in compliance with those requirements. They said the crime lab consistently checks throughout a case to ensure contamination has not occurred. In addition, audits have shown no contamination at the lab.

Both witnesses said the lab uses equipment which is different than Hampikian referenced in his testimony. For example, they utilize tubes with twist caps and bar codes which help to prevent contamination. Those tubes differ from the pop-top type tubes Hampikian showed the jury. In addition, the tray or plate used in the crime lab to hold samples differs from the one Hampikian showed the jury. Buettner also noted that the crime lab used robotics to transport liquids which prevents contamination caused by human error.

“I would in no way say our procedures are sloppy,” said Buettner.

The crime lab, by using STRmix software, determined that Farbourn’s DNA was present on the handle of the knife along with Arce’s DNA and one additional person. They found that DNA from blood found on Fairbourn’s pants consisted of a mixture of DNA from Story, Fairbourn, and another person with Story being the major contributor of that DNA. They also found that Story and Arce’s blood was on the knife blade. Blood on Fairbourn’s shirt belonged to Fairbourn.

The trial will continue on Monday with testimony expected from law enforcement officers.

Read more about the case here.