Forensic Science Lab Questions Essay

3. Carefully felt the sides of the test tube and observed the resulted chemical reaction for about 30 seconds.

294). This means even after a week the blood has been cleaned up, luminol can still detect it. Also after applying luminol, the area needs to be darkened so that blue glow can be emitted. “The iron from the hemoglobin in the blood causes luminol to glow, so a blue glow is produced when the solution is sprayed where there is blood. Only a tiny amount of iron is required to catalyze the reaction” (Helmenstine, 2012). The use of luminol revealed that there were blood stains on the bed sheets and suspected that the woman was killed in her bedroom and that she did not go to work that day or leave the house.

The crime scene investigators took a sample of unburned carpet in order to determine the chemical composition of the carpeting in order to determine what, if any, accelerants were used to start the arson fire. By examining the unburned section of carpet, it gives them a baseline on which to start their testing.

The unknown sample was then heated in boiling water in step 5. The reason for heating the

5. Was there any evidence that some of the copper (II) chloride was left in the beaker? Explain.

At the scene of the crime fingerprints were also found. As a team, we concluded that the fingerprints belonged to Alex Garcia. When comparing the fingerprints at the crime scene and the suspect’s prints, we looked at the ridge pattern and the minutiae. Alex Garcia’s ridge pattern matches the ones at the crime scene, a loop. He says he was at work at the time, but he has no alibi witness. In 2008 Alex Garcia had a restraining order placed on him by his ex-girlfriend do to violence. Alex never did really go to work. If Alex’s fingerprints were at

1. What was the purpose of using water as a sample in some of the tests performed in the lab? (2 points) to have a control.

During the identification phase, the user puts the finger on the same sensor, generating a new fingerprint image or template called query print. Minutiae points are carried out from the query print, and the matcher module compares the set of query minutia with the stored minutia templates or image in the enrollment database to find the number of similar minutia points. Because of variations present in finger placement and pressure applied to the sensor, the minutia points take out from the template and query fingerprints must be lined up, or submitted before matching. After line up the fingerprints, the matcher decides the number of pairs of matching minutiae-two minutiae points that have similar location and directions. The system decides the user's identity by comparing the match score to a

Lee, H. (2001). Advances in Fingerprint Technology, Second Edition, 2nd Edition. Retrieved January 26, 2015, from Vital Source: http://online.vitalsource.com/books/9781420041347

scientific law enforcement in his creation of a mass fingerprint file in 1926 and the

Before 1999 it took about 3 months to be able to find a matching fingerprint, now it takes 24 hours or less because it is now computer ran which is just one of the many benefits of this database. IAFIS has three ways that is can be used and how it's helpful. First is the criminal history this database keeps is a wide range of fingerprints, photographs and information on people who work for the government. Next it provides positive fingerprint identification. Lastly it can provide identification just by punching in in somebody’s name, DOB, specific body markings (such as tattoos), and identification numbers. The only people who are allowed to use IAFIS though are people within in the FBI. This database is also operated by a section of the FBI called the Criminal Justice Information Service

After Galton’s discovery, the use of fingerprinting by law enforcement was inevitable. In 1892, an Argentine police official, Juan Vucetich, became the first person to identify a criminal through fingerprints (The History of Fingerprints). The last major step necessary for the widespread use of fingerprint identification was to create a classification system that simplified the process of matching fingerprints. That came in 1901, when Edward Henry devised a system that separated fingerprints into four different categories - loops, whorls, arches, and composites (Skopitz). Shortly after its development, most European nations implemented this system of

3. (5 pts) List two of the bits of evidence that you think were the most important findings in linking the exposure in question to the disease. (In other words if you had to explain the investigation to someone using only 2 details from the investigation, which two would you pick? Explain your logic for each one.

The automated Fingerprint Identification System is also known as the AFIS within the law enforcement division (FBI, 2010). This system is an important element in the criminal justice system as some of its features encompass the storing of data, encoding, and fingerprint and facial comparison through graphics and other techniques. Law officials many centuries ago in the pursuit of positively identifying someone suspected of guilt have long used fingerprints techniques. Fingerprinting is also used in branches of our government, and in the Pentagon, the authentication method of fingerprints is used permit access to specified zones inside the building. Fingerprints are an effective and very precise method of identification purposes that does not pose

Fingerprinting is used for many things, such as a robbery, or at a crime scene. Fingerprints were first discovered in 1870 by Alphonse Bertillon, who was a French anthropologist. In 1892, Juan Vucetich had made the first criminal report using a fingerprint. In 1905 America used fingerprints for identification. When America started using fingerprints for identification they had to match the fingerprints manually when needed. When technology was able to enter fingerprints, and match them with anonymous ones, it helped identification immensely.