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Fingerprinting. Fingerprints that are collected at a crime scene can be used to identify people who were at the crime scene, such as a suspect or victim.No two fingerprints are alike due to the minutiae or ridges.The Henry classification system divides fingerprints into 3 patterns, loops, whorls, and arches..
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3. Error rates in Fingerprinting In the field of fingerprinting, there have been many claims of zero-error. However proficiency tests conducted since 1983, show an aggregated error rate of 0.8 percent. In 2004, the “50k Study” was conducted where 50,000 pre-existing images of fingerprints were compared against one another electronically, producing 2.5 billion comparisons. The study concluded that mistaking one image for another was 1 in 1097. However, Meagher himself stated that the study was not about error rate and critics said that the study does not back up infallibility of fingerprinting.
4. Ballistic Fingerprinting The technique that is used to match a bullet to a specific firearm by matching up the unique markings, or striations.
5. Error Rates in Ballistic Fingerprinting Ballistics in forensic science is used by matching marks on bullets with specific firearms. This field of forensic science is prone to errors however. Criminals can easily purchase firearms through straw purchases or providing invalid IDs. Guns can also be modified to create a unique signature that is not available to current databases. Also, criminals can simply use a gun that does not eject casings such as a revolver. It has been shown that current computer matching systems do not provide accurate results. The Detroit Police Department’s crime lab was shut down when the sate of Michigan found a 10 percent error rate in ballistics identification.
6. Document Examination There had been lots of forgery happening earlier on in the country and Albert S. Osborn created a field of forensic study to deal with this problem.
Forensic scientists have to identify handwriting, signatures, alterations, photocopies, erasures, etc.
No two people’s handwriting is alike and scientists have to indentify these small variations.
7. Error Rates in Document Examination In a study conducted, experts and non experts were tested for proficiency in handwriting identification. Error rate for the experts was 6.5% where as error rate for non experts was 38.3%. However another study conducted using the same scenario found that experts had an error rate of 1% while non experts had an error rate of 6.47% when false signatures were declared authentic. When authentic signatures were declared fake, experts had an error rate of 7.05% while non experts had an error rate of 26.1%. Those studies show that even the experts are highly prone to error.
8. Hair Analysis There are 3 types of hair analysis conducted by forensic scientists
Chemical assays to detect the use of illegal drugs, presence of heavy metals, and nutritional deficiencies.
DNA analysis of the root
Microscopic comparison of the hair to determine whether it is animal or not
9. Error Rates in Hair Analysis A 2004 Justice Department study of 240 crime labs found that hair comparison error rates ranged from 28-68%. In fact hair comparison testimony is outlawed in Michigan and Illinois due to its high rate of error. Another study conducted by the FBI showed that matching hairs using subjective analysis contained a 12.5% error rate, now being replaced by DNA analysis.
10. Arson Investigations Arson investigations are when forensic scientists arrive at a crime scene where there was a fire, and try to determine what the cause of the fire was and who caused it.
Forensic scientists usually start by trying to find where the fire originated from.
11. Error Rates in Arson Investigation When arson investigation began emerging in the forensic science scene, investigators used different “facts” such as “fires started with accelerants burn hotter” have been disproved. “Pour patterns” which have been previously used to show causes of arson can be mistaken for the natural phenomenon of “flashovers” which occurs when enough smoke and gas accumulate in a room to explode into flames. The Daubert “gatekeeping” methodology used to determine if arson was the cause is correct only 40% of the time but that same machine is able to determine the absence of arson 98% of the time, which isn’t too useful for arson investigators.
12. Forensic Dentistry Forensic dentistry is when bite marks are analyzed to match a specific person to a set of bite marks on a victim.
Forensic scientists started bite mark comparisons because they noticed that in cases of battery rape and homicide that victims often had bite impressions on their skin.
13. Error Rates in Forensic Dentistry Bite marks are not like DNA, and cannot be linked to an individual with 100% certainty.
Some people dislike the use of forensic dentistry to identify a suspect, they believe it should be used instead to eliminate a suspect.
14. DNA Profiling DNA Profiling is when DNA is collected, processed, and analyzed so that the samples are individualized and VNTR bands are used for identification
15. Error Rates In DNA Profiling Every 1 in 100 profiles may be a false result.
DNA samples can be contaminated by criminals
RFLP is outdated
Errors may occur when DNA samples are not of high quality
16. The Case of Guy Paul Morin Was accused of murdering and sexually assaulting Christine Jessop
Was acquitted at first his first trial in 1986
However was convicted six years later after another trial in 1992
He was then exonerated in 1995 in light of new DNA testing
It was not a lack of technology that convicted him in the first place but a series of forensic errors
Nearly all the evidence collected against Morin was flawed
17. The Case of Guy Paul Morin cont… When he was granted his appeal the numerous errors began to surface
One key was a cigarette butt at the crime scene that was present in photographs but lost during processing which could have belonged to the true suspect
Also of the 149 fibers collected as evidence from Morin’s home only 1 matched the fibers found on the victim
Only 15 hair samples were collected even though 50 are required
18. The Case of Guy Paul Morin cont… The autopsy also left out major details concerning the injuries the victim sustained
The evidence of Morin’s professed guilt during his interogation was also flawed seeing how there were “technicalities during the interrogation” so it was not recorded
This cases demonstrates various forms of forensic error
19. The Case of Stephan Cowans Was sentenced to 35-45 years in prison for the shooting of Boston police officer Gregory Gallagher in 1998
After Serving 6 years of his sentence his case was reinvestigated by the innocence project
After the evidence was reprocessed he was found to be innocent as the evidence against him proved to be unequivocally false
20. The Case of Stephan Cowans The DNA used to convict him did not match samples left by the true suspect on a glass of water and baseball cap
Also the fingerprint used for conviction did not match Cowan’s it was knowingly falsified
His conviction was based solely on the testimony of questionable witnesses not on forensic evidence
21. The Case of Cameron Todd Willingham Willingham was convicted of murdering his three children via “arson” in 1992
Despite pleading his innocence and having little conclusive evidence against him he was sentence to death
He was executed via lethal injection in 2004
Five years later a article was published in the magazine the New Yorker that proved his innocence
22. The Case of Cameron Todd Willingham cont…. The evidence against him was all speculative nothing was based on fact
According to fire chief Manuel Vasquez he used an accelerant to start the fire and blocked the only exit with a refrigerator
In actuality however it was accidental and the fridge was unrelated
Other “evidence” against him claimed that he was a sociopath because of his posters of Iron Maiden and Led Zeppelin
23. The Case of Cameron Todd Willingham cont… The evidence against Willingham not based on forensic procedure but on conjecture
Not only was he innocent but was the first and only person to ever receive the death penalty for arson
Was not able to appeal his case one of many rights he was denied
24. References http://www.today.ucla.edu/portal/ut/how-scientific-is-forensic-science-82933.aspx (slide 2)
http://reason.com/archives/2007/10/24/breaking-up-the-forensics-mono (slide 2)
http://www.slate.com/id/2197284/pagenum/all/ (slide 2)
http://ezinearticles.com/?Fingerprinting-in-Forensic-Science&id=410615 (slide 3)
http://www.crime-scene-investigator.net/FingerprintScience.html(slide 4)
http://www.sciencedaily.com/releases/2005/09/050913124509.htm(slide 4)
http://www.newscientist.com/article/mg18725174.500(slide 4)
http://www.enotes.com/forensic-science/ballistic-fingerprints (slide 5)
http://www.popularmechanics.com/technology/military_law/4325797.html?page=2(slide 6)
http://www.safde.org/whatwedo.htm (slide 7)
25. References http://www.popularmechanics.com/technology/military_law/4325797.html?page=2 (slide 8)
http://www.enotes.com/forensic-science/hair-analysis (slide 9)
http://books.google.com/books?id=Zl9J5BzK8NgC&pg=PT366&lpg=PT366&dq=hair+analysis+michigan+illinois+error+rate&source=bl&ots=f0xwnt6b01&sig=eSUmVRzXQLDUSSHslsiyycYaeMQ&hl=en&ei=ke4FS5zGNcHelAfgzrWgDA&sa=X&oi=book_result&ct=result&resnum=1&ved=0CAgQ6AEwAA#v=onepage&q=hair%20analysis%20michigan%20illinois%20error%20rate&f=false(slide 10)
http://ezinearticles.com/?Forensic-Arson-Investigation---How-Do-Investigators-Determine-Where-a-Fire-Started?&id=641269( slide 11)
http://firechief.com/mag/firefighting_experts_new_clothes/ (slide 12)
26. References
http://books.google.com/books?id=Zl9J5BzK8NgC&pg=PT366&lpg=PT366&dq=hair+analysis+michigan+illinois+error+rate&source=bl&ots=f0xwnt6b01&sig=eSUmVRzXQLDUSSHslsiyycYaeMQ&hl=en&ei=ke4FS5zGNcHelAfgzrWgDA&sa=X&oi=book_result&ct=result&resnum=1&ved=0CAgQ6AEwAA#v=onepage&q=hair%20analysis%20michigan%20illinois%20error%20rate&f=false (slide 12)
http://www.apsu.edu/oconnort/3210/3210lect02c.htm (slide 13)
http://science.howstuffworks.com/dna-profiling.htm(slides 15&16)
http://www.uplink.com.au/lawlibrary/Documents/Docs/Doc52.html(slides 16, 17, 18)
http://truthinjustice.org/Cowans-framed.htm(slide 20,21)
http://www.corpus-delicti.com/forensic_mis.html (slide 20,21)
http://www.newyorker.com/reporting/2009/09/07/090907fa_fact_grann?currentPage=all (slides 21, 22, 23)
http://www.newyorker.com/reporting/2009/09/07/090907fa_fact_grann (slides 21, 22, 23)
