An examination comparing bullet fragments recovered from the Opal Fairchild murder and violent robbery of Mel Anderson show fragments from the two crimes were fired from the same type of handgun, according to expert witness testimony.
In the murder trial of Barry McCormack, jurors heard testimony from two forensic firearms experts who compared bullet fragments from the two crime scenes.
Robert Shem, a firearms forensic firearms expert with the Alaska State Crime Lab who compared the bullet fragments in 2003 said the bullets were fired from the same type of gun, a 38 class handgun, but was less certain the bullets were fired from the same individual gun.
He said the chance that the bullets were fired from the same gun was a “good could be.”
“(But) I wouldn’t want to stake my carrier on it,” he said.
Shem walked jurors through the steps forensic firearms experts take to determine whether two or more fired bullets were fired from the same gun, when the gun is missing or not available for analysis.
Investigators have not yet located the gun, or guns, that fired the bullet fragments found at the Fairchild murder case and Anderson robbery.
Shem explained that gun barrels are lined with groves that spiral either to the left or the right as they travel to the end of the gun.
When a bullet is fired from a gun, the grooves spin the bullet, similar to the way a football player throws a football through the air. This prevents the bullet from tumbling forward and improves the accuracy of the gun’s aim.
But the grooves are also valuable in helping forensic firearms experts compare bullets. Grooves engrave identifiable marks on bullets fired from them. And the number, width and direction of the grooves found in guns vary depending on the gun’s model and make.
The marks found on bullet fragments retrieved from the Fairchild and Anderson crime scenes show they were fired from a gun barrel that had five grooves, and that the spacing between the grooves was equal to the width of the grooves.
And the bullet fragment analyzed from the Fairchild murder was marked by grooves that spiral to the right, but the bullet fragment analyzed from the Anderson robbery was not large enough to determine the spiral direction of the grooves, Shem said.
Once Shem determined the bullet fragments found at both crimes were likely to have been fired from the same type of gun, he then looked for finer marking details to identify whether or not the bullets were not only fired by the same type of gun, but the same individual gun.
Two guns of the same model and make will produce the same spiral groove markings, but manufacturing imperfections and wear and tear give each gun its own individual signature in the form of fine scratches.
And while Shem said he did not match enough individual markings on the bullet fragments from the Fairchild murder to the Anderson robbery to determine whether the bullets were fired from the same individual gun, he said it was possible some of the individual markings had deteriorated before he compared the bullet fragments, almost 20 years after the bullets were fired.
However, FBI forensic firearms expert Paul Schrecker compared the bullet fragments in 1985, the same year they were fired, and said his examination showed that the bullets were likely to have been fired not only from the same type of gun, but the same individual gun.
Shem, however, said forensic experts cannot be absolutely certain the bullets were fired from the same without the gun.
“The only way you can know for sure is when you can match them back to the gun,” he said. said.
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