CORVALLIS, Ore. - A proven forensic technology that two decades ago helped convict the "I-5 Bandit," one of the more notorious criminals in Oregon history, now lies in comparative disuse with many top law enforcement officials unaware it even exists.
That may soon change, say scientists at Oregon State University, when the university and this technology is featured on the television series "The New Detectives" on the Discovery Channel. Filming will begin on the Corvallis campus on April 9.
The real mystery, researchers say, is why there isn't more use of this sophisticated technology called "neutron activation analysis" to help solve crimes, convict the guilty and exonerate the innocent.
"A lot of FBI agents don't even know about this technology and what it can do," said Brian Dodd, a professor of nuclear engineering and director of the Radiation Center at OSU. "This is a powerful and accurate technique, not particularly expensive, and it can identify trace elements at levels as low as one part in 10 billion."
The catch, Dodd said, is that it takes at least a research nuclear reactor to make the technology work, which OSU has but most crime labs obviously do not. And the expertise to conduct these tests is not all that common. OSU is one of only a handful of science facilities in the nation that do neutron activation analysis, and "it would be difficult to get someone to certify the scientific accuracy of our technology because we know more about it than anyone else does," Dodd said.
Right now, OSU researchers are using neutron activation analysis about 4,000 times a year in more mundane research such as the testing of geological mineral samples. It's vast potential in criminal investigations is largely untapped, accounting for only 30-40 cases in the past three decades.
There have been exceptions. The technology, for instance, is great for telling if the trace element composition of a bullet from a crime scene matches other bullets found in the possession of a suspect. In 1981, that ability helped stop the assault, rape, robbery and murder spree of Randall Woodfield, who was convicted of multiple crimes up and down the I-5 corridor in Oregon, Washington and California.
"The testimony of OSU experts and findings of our neutron activation analysis carried a lot of weight in the conviction of Woodfield," said Mike Conrady, an OSU specialist in this technology. "We helped match a bullet taken from a victim's head to one with a similar makeup found in a golf bag in Woodfield's closet."
In recent years, similar work helped solve another murder in Tillamook, Conrady said. It found some matching bullets in a drug-related murder case in Portland. In a hit-and-run automobile accident, the technology matched windshield glass found at the scene to that of a car taken in for urgent repairs at an auto-body shop, and helped lead to a confession in that case.
And in one marine case, paint scrapings taken from the bow of a ship suspected of running over a smaller vessel showed it most likely was not the culprit.
According to Conrady, neutron activation analysis works by using a nuclear reactor to irradiate many common elements, such as sodium, magnesium, zinc, arsenic, cobalt, potassium, and others. When the nucleus of an atom is hit by a neutron it will often absorb the neutron and become a radioactive isotope of that atom. As a radioactive isotope, it then emits gamma rays which can be measured to determine the identity, presence and levels of the original trace element in the sample.
Samples are not destroyed, can be very small, can cost as little as $60 to analyze and large numbers of samples can be run at one time.
"Many common products, whether they be windshield glass, paint or the lead in bullets, may have more or less the same compounds and ingredients in them," Dodd said. "But when you start talking about the trace elements such as antimony or arsenic or silver, they don't have exactly the same elements."
Bullets, for instance, that were made from the same batch of melted lead will all have essentially the same trace element makeup. But the chance that one molten pour of lead will have precise trace element composition matching that of a different batch may be as small as one in 50,000, Dodd said. This makes it possible to create fairly strong circumstantial evidence matching various materials from a crime scene to those found elsewhere.
"We're actually doing less of this forensic work now than we used to," Dodd said. "Personally I think this might be one result of the O.J. Simpson trial, where the DNA and other forensic evidence was subjected to such intense scrutiny and he was later acquitted. I think the district attorneys are spooked."
Dodd said OSU may do more random testing and professional publications with neutron activation analysis to better establish its accuracy, validity and awareness of the technology.