Finger prints have been used for identification ever since the 1800's. The process was lengthy and required the entire print. The reality of it is that at a crime scene, a CSO (Crime Scene Officer) may find over one hundred prints and most of them are partials. Recently, forensic scientists have come up with a way to mathematically calculate the rarity of a print.
Knowing how rare a fingerprint is can help CSO's determine which prints are helpful to the case. The software that calculates this gives a print a series of points and compares it with others. This computer then compiles the evidence and calculates rarity of the print. To date most CSO's do this calculation by hand
“They might find hundreds of prints at a crime scene, and right now the analysis is done intuitively by human examiners,” Dr. Srihari said. “But we can calculate that.”(Dr. Srihari 2010)
Newspaper or Magazine Article:
Bhanoo, Sindya. "Calculating the Rarity of a Fingerprint." The New York Times December 10, 2010: Science, online.
Friday, April 29, 2011
Thursday, April 21, 2011
CSI Improvised Tools of the Trade
Though all CSI's go through difficult and extensive training, sometimes what's learned in the classroom doesn't help in the field. When they encounter obstacles that can not be overcome using there nifty kits, CSI's are required to think "out of the box". Many times a CSI has faced a situation in which they must improvise and find a solution to there problem with the tools given to them. Many "tools of the trade" started as improvisational gadgets thought of by CSI's in the field.
For example, one tool being the Blue Light Special, was created in 1994. This tool was a hand held blue light which allowed Investigators to find urine, semen, and saliva samples at the scene of the crime. Pre-Blue Light Special, the only lights for finding these specimens where huge crime-lab lights which costed upwards of thousands of dollars. So, CSI's had to collect everything they believed contained evidence then bring it back to the lab to examine it. Now with The Blue Light Special the crime scene would no longer have to be completely disturbed.
Another device which started as an improvised gadget is the Eagle-Eye Pole. The Eagle-Eye Pole is a pole that you strap a camera to the end of to be able to take birds-eye view photos. Prior to the Eagle-Eye CSI's would have to call in tree trimers or use latters to raise themselve from the scene to be able to take a photo.
Newspaper or Magazine Article:
Warrington, Dick. "On the Scene: Improvised Tools of the Trade."Forensics Magazine : .
For example, one tool being the Blue Light Special, was created in 1994. This tool was a hand held blue light which allowed Investigators to find urine, semen, and saliva samples at the scene of the crime. Pre-Blue Light Special, the only lights for finding these specimens where huge crime-lab lights which costed upwards of thousands of dollars. So, CSI's had to collect everything they believed contained evidence then bring it back to the lab to examine it. Now with The Blue Light Special the crime scene would no longer have to be completely disturbed.
Another device which started as an improvised gadget is the Eagle-Eye Pole. The Eagle-Eye Pole is a pole that you strap a camera to the end of to be able to take birds-eye view photos. Prior to the Eagle-Eye CSI's would have to call in tree trimers or use latters to raise themselve from the scene to be able to take a photo.
Newspaper or Magazine Article:
Warrington, Dick. "On the Scene: Improvised Tools of the Trade."Forensics Magazine : .
Friday, April 15, 2011
Fingerprints in Forensics.
In the begging fingerprints were first thought of as a form of identification by Sir Henry Edward in 1896. He classified finger prints into the major categories of whorls, loops, and arches. Finger prints where given a set of numbers which were used as a fraction to identify the 10 different fingers in a coded sequence. A fingerprint was given a number code depending on the type of pattern and the finger the print came off of. This system of classification consisted of over 1024 codes which helped catch criminals who had many different identities, aliases.
Criminals who where already convicted before were fingerprinted and inputed into the system. Their prints were matched and compared with other prints found at different scenes. The system did have however have its flaws due to the fact that all 10 fingers needed to be collected. Later on with the invention of computer systems, finger prints became easier to collect and compare. The ability to match prints progressed faster and faster over the years.
To compare prints investigators looked at the ridges and where they start, end, and split. With computers this process became easier where a certain system could automatically record the ridges, whorls, arches or loops. These where then compared to the prints collected and listed in order of most comparable.
Website:
, . "Fingerprinting ." ORACLE ThinkQuest. . . 15 April, 2011. <http://library.thinkquest.org/04oct/00206/text_nts_fingerprinting.htm>.
Criminals who where already convicted before were fingerprinted and inputed into the system. Their prints were matched and compared with other prints found at different scenes. The system did have however have its flaws due to the fact that all 10 fingers needed to be collected. Later on with the invention of computer systems, finger prints became easier to collect and compare. The ability to match prints progressed faster and faster over the years.
To compare prints investigators looked at the ridges and where they start, end, and split. With computers this process became easier where a certain system could automatically record the ridges, whorls, arches or loops. These where then compared to the prints collected and listed in order of most comparable.
Website:
, . "Fingerprinting ." ORACLE ThinkQuest. . . 15 April, 2011. <http://library.thinkquest.org/04oct/00206/text_nts_fingerprinting.htm>.
How does forensic evidence help track and catch criminals?
Where ever you go, what ever you do, you always disturb your environment. Whenever you walk into a room you either leave something or take something with you on the microscopic level. There are hundreds of microscopic pieces of evidence that can link you to specific place at a specific time. Naming a few being DNA trace, fingerprints, hair, sweat, saliva, skin even the brand and chemical make up of the cologne you were can link you to a crime scene. Hours of chemical analysis of a crime scene can bring up hundreds of pieces of evidence that can narrow down suspects. Though the process may not be as fast as you see on CSI: Miami, the idea of it is dead on. Throughout the next 18 weeks of research I hope to better understand how is it that getting away with a crime is technically impossible, thanks to forensic evidence.
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