Question

7. Discuss ALL possible forensic analyzes you could do for the following sample evidences and explain how each analysis is being done to obtain conclusion. (Answers in 300 + 10 total words.) A. Blood on the floor after a crime b. Debris collected after fire in a building c. Paper signed with blank ink for forgery investigation d. Fingerprint on paper.

Answer 1

7. Ans- A. Blood on the floor after a crime - Blood evidence detected at a crime scene by forensic investigators using luminol to detect trace amounts of blood at crime scenes, as it reacts with the iron in haemoglobin. Biologists use it cellular assays to detect copper, iron, cyanides, as well as specific proteins via Western blotting. Studies have shown that when blood is released during an attack certain patterns of blood spatter distribution can be expected. Blood from the victim adhering distributed when upstroke for the next strike. Calculations of how many strikes were made may become evident from the tracking of multiple streams of droplets behind the victim and behind the attacker. Given this developing science, blood spatter analysis can be useful in criminal event reconstruction.

B. Debris collected after fire in a building- This is a part of fire investigation which is an unenviable task. The basic role of an investigator at a fire scene is two fold they are- firstly to determine origin of the fire and secondly to examine closely the site of origin to try and determine what it was that caused a fire to start at or around that location. Fire debris is a general term used , when fire investigators suspects that a fire might have been deliberately set using accelerants such as, ignitable liquids. It is possible to collect and analysis fire debris to see if such products are present. Once the analysis is done , it is important to interpret the results carefully. Only the proper collection, examination, analysis and interpretation of the fire debris sample allow the forensic investigators to reach the proper conclusion . Results may be reported due to lack of comparison standard can make identification difficult, the flamMable accelerant or lab standard can be identified as consistent in origin with a submitted control, the laboratory did not detect ignitable liquids as being present in the fire debris.

C. Paper signed with blank ink for forgery investigation- forgery typically is defined as writing or altering a document with the intent to defraud. Forensic examiners check this forgery under microscope. A typical signed paper with blank ink unit in a crime laboratory is equipped with microscopes, digital imaging instrumentation, infrared and UV sources , video analysis tools and specialized equipment including EDD.

D. Fingerprint on paper- Fingerprints examiners use the ACE-V method to reach a determination on each print. Analysis- involves assessing a print to determine if it can be used for a comparison. If the print is not suitable for comparison because of inadequate quality or quantity of features, the examination ends and the print is reported as not suitable. If the print is suitable, the analysis indicates the feature to be used in the comparison and their tolerances. The analysis may also uncover physical features that help indicate where to begin the comparison. Comparisons- are performed by an analyst who vies the known and suspect prints side-by-side. The analyst minutiae characteristics and locations to determine if they match. Known prints are collected from persons of interest, victims, others present at the scene or through a search of one or more fingerprint databases suc as IAFIS. Evaluation- is where the examiner ultimately decides if the prints are from same source, different sources or is inclusive. Inclusive results may be due to poor quality samples, lack of comparable areas or insufficient number of corresponding. Verification- is when another examiner independently analyse, compares, and evaluates the prints to either support or refute the conclusion of the original examiner. The examiner may also verify the suitability of determinations made in the analysis phase.