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Shaking the Faith in Science

Fake DNA prompts change in criminal forensics

By Polly Cambron · January 13th, 2010 · News
America’s fascination with the use of forensic science to solve crimes is best proven by the explosion of TV shows dealing with the topic, from dramas like CSI and Cold Case to reality shows like Forensic Files and The Bureau.

During the past two decades, advances in forensics — the use of science and technology to investigate and establish facts in courts of law — have led to a seismic change in how police work is conducted and what jurors expect when hearing a case.

Although forensic evidence is available only in 10 to 20 percent of all criminal cases, the public places great weight on its inclusion, a fact that’s keenly aware to prosecutors and defense attorneys. Perhaps the main reason is improvements made in DNA profiling, or the analysis of human material like blood, semen, skin tissue or hair that can be used to precisely identify an individual.

The best-known example of DNA profiling’s impact is the Innocence Project, a nationwide non-profit group that uses testing to determine if a prisoner has been wrongfully convicted. Since the group began in 1992, more than 240 people in the United States have been exonerated, including 17 who were waiting to be executed on Death Row.

Just last month, the longest-incarcerated victim of a wrongful conviction was freed due to the Innocence Project’s work. James Bain — who had been imprisoned for 35 years for kidnapping, rape and burglary — was exonerated by DNA testing. Before the project’s involvement, his appeal was denied four times by the courts.

But forensics came under fire last summer when scientists in Israel were able to create DNA evidence capable of identifying the wrong person, causing profiling’s supposed infallibility to become suspect. The same bio-tech firm that did the research, however, has developed a system to detect the difference between natural and manufactured DNA, based on the lack of methylation — a chemical reaction — in the artificial sample.

Local DNA experts say the techniques should be scrutinized to make sure the procedures used are valid and rigidly follow the Daubert Standard, a standard of testing under which a trial judge has a duty to dissect evidence rigorously to determine whether it has been established as reliable and scientifically valid.

Some of the procedures that judges must consider include whether valid testing protocols were used, if the evidence has undergone peer review among the scientific community, error rates and acceptability in the general forensic science community.

The Daubert Standard came about from the 1993 case of Daubert v.

Merrell Dow Pharmaceuticals, which examined the adequacy of cutting-edge scientific testing techniques.

Elizabeth Murray, a Cincinnati-based biological and forensic anthropologist, has been at the forefront of forensic scientific research for several years. She’s written about the importance of conducting research that allows forensic techniques to satisfy current Daubert standards.

“Essentially some of us were already seeing that the field needs to test its methods and certify its practitioners,” Murray says. “We simply cannot just be expert witnesses by virtue of years in the field anymore. Our methods need validity and hopefully these mandates will push practitioners and research in that direction.”

One example of tightening standards involves how to properly retrieve and identify bullets from crime scenes. John Heile, a criminologist who specializes in ballistics and tool mark analysis for the Hamilton County Coroner’s Office, explains the different aspects of evidence retrieval.

Heile says, “(T)here are standards we use in order to reinforce our identification which include statistical data, secondary and tertiary verification from colleagues, (and) we reinforce our examination using sufficient objective analysis.”

In another case, Heile was called upon to analyze “hatchet marks in the paint on the siding of a house involved in arson. This involved submitting the siding to the lab where test marks and comparisons were made on marks left by the blade until I could begin to identify individual characteristics of the actual tool that was used.”

Heile was able to identify the hatchet used to cut the siding away in order to start the fire by examining individual characteristics found on the blade such as rough edges and atypical markings.

Forensics isn’t only changing how criminal cases are conducted. Advances in technology also are being used to solve mysteries caused by even everyday mundane occurrences like fender benders.

Dan Aerni, owner of MV Engineering in Oakley and a vehicular accident analyst, credits General Electric for leading the way in “electronic data recorders, known as black boxes, which were originally installed for anti-lock braking systems. (They) are now a key feature in accident analysis, another piece of the puzzle for us.”

The data collected from the black boxes is evaluated with tools including electronic distance measuring equipment, computer-based mapping, laser measurement analysis and mathematical validation. The question of who broke the law or who is at fault in an auto accident can now be answered within computer precision, Aerni says.

Digital evidence retrieved from computers is another aspect of forensics undergoing change as it becomes relied on more often by law enforcement.

Jim Swauger, of Binary Intelligence in Lebanon, just north of Cincinnati, specializes in computer forensics, electronic discovery and corporate investigations. A court-recognized expert with more than a decade of experience, Swauger has served as senior computer forensic specialist for the Ohio Bureau of Criminal Investigation.

Nowadays, criminal suspects shouldn’t rely on simply deleting incriminating information from their computers.

“Deleted or damaged evidence can be retrieved from flash memory modules, digital cameras, mobile phones, iPods, DVRs and PDAs, and examiners can find data protected by very strong cryptographic algorithms,” Swauger adds.



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