The next step is evidence collection. Processing a crime scene without disturbing the evidences is a difficult task and investigators should take every precaution to gather evidence without affecting the crime scene. (GSA) Crime scene stepping pads' can be used for walking around the area without damaging potential evidences. Photographs and video must be taken before proceeding with the rough sketching around the crime scene. For this purpose 'crime scene sketch kits' must be used. Evidence should be gathered using appropriate evidence collection tools so as not to erase the fingerprints or cause any other damage. It is important for the investigator to carefully consider and gather even microparticle evidences using micro evidence gathering kit. Evidences gathered should be properly catalogued and stored in 'tamper resistant evidence bags'. Evidence collection envelopes with transparent or viewing capabilities are appropriate as they allow for physical examination of the evidence without having opening the packs. Also, evidence bags pre-printed with identification data offer an easy way to collect, store, record and present information from the crime scene. (GSA)

3) in spite of the rapid advancements such as DNA analysis, fingerprints still continue to be the mainstay method of identification in criminal investigations. Optical, physical and chemical processes are the three main methods of enhancing latent fingerprints. The appropriateness of any one particular method is usually determined by the nature of the crime scene. However, optical processes offer the best non-destructive method of fingerprint analysis. Even in cases of fingerprints processed by chemical and physical methods, optical processes such a colouring; luminescence, etc. enhance the fingerprints significantly. Latent fingerprints are most difficult to process and it is essential for the analyst to have an excellent knowledge of human secretions and environmental effects. Fingerprint powders are used to detect specific chemical compounds. (Aluminium powders, magnetic powders, luminescent powders, etc.) However, successful detection using fingerprint powders requires the presence of at least 500 to 1000ng of the material. Even then powdering continues to be the most common fingerprint identification technique.

Other methods such as ninhydrin coloring and luminescence detection suing DFO reagent are more sensitive and hence...

Physical development can be used separately or in addition to DFO treatment. This process is similar to the common photographic development process using silver nitrate solution. (Dr. Chris Lennard (2001)). Arches, whorls, loops and composites are the four different patterns under which fingerprints are classified. Earlier, comparing fingerprints used to be manual and time consuming. Today, however computers can match a persons fingerprint with more than a million fingerprints stored in its database in a few seconds. This is possible because the FBI and the National Crime Information Center (NCIC) use automated fingerprint identification systems using the standardised fingerprint classification system called the FPC. The computer generates a geometric graph based on the positions of the ridge endings and the ridge branching. Experts then compare closely matching results from the computer search for exact identification. (Courtroom Television Network).
Bibliography

Kevin Bonsor, "How Lie Detectors Work," Retrieved on 21st May 2007, at http://www.howstuffworks.com/lie-detector.htm

EPIC, "Polygraph Testing," Retrieved on 21st May 2007, at http://www.epic.org/privacy/polygraph/

BCSSE, "The Polygraph and Lie Detection," Retrieved on 21st May 2007, at http://books.nap.edu/openbook.php?record_id=10420&page=212

Gerry Everding (2004), "Research casts doubt on voice-stress lie detection technology," retrieved on 21st May 2007, at http://news-info.wustl.edu/news/page/normal/669.html

University of Missouri, "Computer Voice Stress Analyser," Retrieved on 21st May 2007, at http://campus.umr.edu/police/cvsa/cvsaintr.htm

GSA, "The Crime Scene," Retrieved on 22nd May 2007, at http://www.leacorp.com/pdfs/Forensic_Supply_Products/6_evidence.pdf

8) Dr. Chris Lennard (2001), "The Detection and Enhancement of Latent Fingerprints," retrieved on 22nd May 2007, at http://www.interpol.int/Public/Forensic/IFSS/meeting13/SpecialPresentation.pdf

Courtroom Television Network, "Forensic Identification - Prints," Retrieved on 22nd May 2007, at http://www.crimelibrary.com/criminal_mind/forensics/crimescene/6.html