AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |
Back to Blog
Fingerprint analysis12/16/2023 ![]() ![]() The National Academy of Sciences report made a host of recommendations for shoring up the validity and reliability of forensic practices. While it may or may not be true that no two prints are exactly alike, there are plenty of very similar prints. When a latent print is pulled off a piece of evidence - in the Mayfield case, it was lifted from a bag of detonators - but there is no suspect already identified for comparison purposes, an examiner can feed the crime scene print into the system, which generates a list of potential matches based on similar characteristics. Implicated in the Mayfield fiasco was a common issue in fingerprint analysis known as a “close non-match.” This is particularly problematic with analyses aided by the Automated Fingerprint Identification System, a database of millions of prints maintained by the FBI. Moreover, crime scene prints are often distorted - or, “noisy” - partial prints that may be smudged or otherwise degraded, which is where errors occur, as in the infamous case of Brandon Mayfield, the Oregon lawyer who was wrongly suspected of being involved in the 2004 Madrid train bombing based on the FBI’s faulty fingerprint analysis. While experts have long said that no two prints are the same, there’s no proof that is the case. This includes fingerprint, or friction ridge, analysis, along with things like handwriting analysis and bite-mark matching.įriction ridge analysis rests on a deceptively simple foundation: that human fingerprints are unique - an individuality that persists - and that this uniqueness can be transferred with fidelity to a substrate, like glass or paper. This was true for all of the so-called pattern-matching disciplines, where a practitioner takes a piece of crime scene evidence and attempts to match it to a pattern known to be associated with a suspect, a process that is highly subjective. Aside from DNA analysis, the majority of the forensic disciplines lacked meaningful scientific underpinning, the report concluded. The release of a groundbreaking report from the National Academy of Sciences in 2009 threw a harsh light on the state of forensic science. ![]() Not least among them: What, if anything, do proficiency tests say about the abilities of the forensic examiners taking them? Startling False Positive Rates But the lawyers also knew from cross-examinations that these same analysts appeared to know frighteningly little about their discipline, and they worked in a lab setting that had none of the written policies or quality assurance practices designed to keep forensic work well-documented and reliable.Īs proficiency testing has become ubiquitous in the forensic sciences - according to federal data, 98 percent of practitioners working in accredited public crime labs are proficiency tested - the disconnect Max and his colleagues face in Chicago raises a series of sobering questions. If they could so easily pass the test with zero training to guide their analysis, what did that say about the test’s ability to accurately assess the competency of any fingerprint examiner, including the six employed by the Chicago Police Department, whose work they regularly had to vet when defending clients?Īcing the tests, which the CPD examiners regularly did, allowed them to bolster their credibility in court regarding their conclusions about matches between a crime scene print and a criminal defendant. But they were certain this was not a good thing. So, nominally, it was good news: Each of them had correctly identified all but one of the fingerprints contained in the test. None of them had any training or real expertise in latent fingerprint analysis - the practice of trying to match a fingerprint collected from a crime scene to the known print of a suspect - aside from what they’d learned during their years working criminal defense. Actually, it was the same news: The three lawyers had nearly aced a proficiency test designed for fingerprint examiners. Brendan Max and two of his colleagues in the Cook County, Illinois, public defender’s office got some good news and some bad news in the spring of 2018.
0 Comments
Read More
Leave a Reply. |