I love watching CSI on television. I like the gadgets and secretly wish to shine that fancy purple light in a darkened room and find the blood traces and solve the crime. The closest I get to dealing with forensic science is in my law practice.
These shows have become so popular that the CSI effect has developed within criminal law. Jurors have seen so much of this stuff in movies and on TV that their expectations exceed reality. They are disappointed and irritated when life doesn’t imitate art.
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Another offshoot of the CSI effect is that people tend to believe forensics are perfect and infallible and lab technicians never make a mistake. If there is scientific proof of a crime, it is accepted as proof positive that the accused person is guilty.
Forensics have proven invaluable in solving crimes, but they are often flawed.
The current exception is DNA sampling and testing. Science tells us that once a positive DNA match is made, the odds of it being incorrect are one in 113 billion by FBI estimates. DNA has been used to clear people who have been wrongfully convicted of crimes.
But DNA is not perfect. In the spring of 2007, federal auditor general Sheila Fraser wrote a report critical of the RCMP labs’ backlog of DNA analyses, noting that urgent requests (about one percent of the total) could be met within 15 days, but the rest could not meet a 30-day deadline.
She noted there were serious quality control issues within the six RCMP labs in Canada. While DNA testing is an effective and scientifically proven investigative tool, it is still subject to human error.
However, recent events show that other areas of forensic science are open to real scrutiny. Dr. Charles Smith, an Ontario pathologist, ran such a substandard practice that 40 cases in which his forensic work played a large part in gaining convictions for serious crimes, including murder, were reviewed. Numerous people were found to have been wrongfully convicted and now are free.
Lives were ruined due to a combination of shoddy forensic work and jurors’ willingness to believe virtually anything a forensic examiner tells them.
Other areas have come into question. Ballistics evidence, long accepted as reliable, has been shown to have unsubstantiated scientific value. There has been no large-scale statistical testing run to see how often the ballistics analyses are correct.
Without that, there is no way to know whether ballistics testing is sound and reliable.
In September 2008, the Detroit police department’s crime lab was closed after quality control experts discovered this lab had made one out of 10 errors in ballistics analysis. One in 10 suspects was likely wrongfully convicted and sent to prison.
Fingerprint evidence is also seen as conclusive by most judges and juries, but there is no statistical analysis to back up what fingerprint experts say.
In 1788, a German doctor declared that no two people could have the same prints. In 1892, Sir Francis Galton did some statistical analysis and concluded fingerprints should be used in crime detection. Fingerprinting for police purposes is based upon their theories.
Recent studies show that people can have the same fingerprints or at least similar enough prints to cause false results.
When a TV show demonstrates a computer making rapid findings and matches, it’s fiction, not fact. It is a human examiner who makes the final call as to whether it’s a match.
In the U.S., an experiment had highly experienced fingerprint examiners investigate numerous fingerprints. They weren’t told they’d be looking at the same prints twice.
Each examiner came to different findings regarding the same prints, every time. It’s not just the science, but the fact that humans are interpreting the scientific data and making findings, leading to opinion. Opinions can be wrong.
Finally, trace or sample evidence is open to question.
Matching paint scrapes from a car accident is actually quite reliable because there is a chemical basis for the science.
But fibre matching of clothing or carpets is less reliable.
Fibres can be shown to have probably come from the same garment or rug, not that they definitely did.
This column presents some of the problems and challenges with forensic evidence.
Next week, I’ll discuss what can be done to deal with these problems.
Rick Danyliuk is a practising lawyer in Saskatoon with McDougall Gauley LLP. He also has experience in teaching and writing about legal issues. His columns are intended as general advice only. He can be reached at thelaw@producer.com.
