DNA Laboratory Errors That Sent Wrong Man to Prison
The introduction of genetic evidence into the courtroom is making justice more certain, for both the guilty and the innocent. Thanks to advancements in science and technology, law enforcement officials and prosecutors are relying more and more on DNA evidence during criminal investigations and trials of criminal cases in order to prove with certainty that someone committed a crime.
But clerical errors in DNA handling and interpretation have caused the innocents to be convicted of crimes.
In 1999, a sample taken from a burglary scene had matched to six loci on the DNA molecule of one of 700,000 persons in national database. The suspect had alibis and incapable to commit the crime and yet, he was wrongfully took in for imprisonment.
The reasoning was that his DNA pattern would occur only once in 37 million individuals. Despite the statistical calculation of 1 in 37 million on six loci, however it does NOT mean that the six loci cannot match more than one person in 37 million.
According to population geneticists, it is indeed possible to have the six loci match in perhaps many dozens of individuals whose DNA is contained in a databank of 700,000. The police in Great Britain maintain a DNA database that has grown from 470,000 potential suspects in 1998 to over 700,000 during 1999. The Forensic Science Service manages the U.K. database.
It is now reported that ten loci will henceforth be used routinely when comparing known samples against unknown DNA fragments. The FBI is reported to test 13 different loci, which minimizes the chance of matching an innocent suspect by chance.
This misinterpretation of the statistical results in light of the case circumstances was revealed by British authorities only in January of 2000 when a law enforcement conference of DNA specialists worldwide meeting. That was 6 months freedom of the innocently convicted that has been luckily cleared off from his ‘conviction’.
This month, Illinois fired its DNA lab, Fairfax County-based Bode Technology, for failing to detect semen in 11 out of 51 rape cases. State police said the errors had not wrongly freed or convicted anyone, but they said they would have to reanalyze evidence in 1,200 rape cases.
At a July murder trial in Michigan, prosecutors acknowledged that a DNA test on evidence from 1969 matched someone who would have been 4 years old at the time of the slaying and couldn’t possibly have been involved. Additional tests led to a second man, who was convicted.
DNA reliability has been lauded nationally as the most reliable evidence known. It is just miscalculation in a lot of factors, which should not happen.