At a time when eye witness's evidence is difficult to obtain, mainly because no one is willing to come forward to stand as eye witness and even in those few cases where the eye witnesses are available they may turn hostile at the time of adjudication it became necessary to look for alternative. Moreover due to phenomenal advancements in Science and Technology the smart new hi-tech criminal is able to commit crimes. Because of these complexities in the investigation of crime, many crimes now a days are remaining undetected and few other crimes where detection although becomes possible, due to technical trivialities and legal loopholes the criminal is escaping unpunished. The result of all this is many criminals are committing crimes repeatedly, undeterred and unchecked and thereby all law abiding citizens are losing confidence in the Criminal Justice Administration.
The Police in advanced countries are utilising latest scientific tools for identification and collection of all available physical evidence by qualified and skilled scientific personnel. The result of such scientific approach right from collection of Physical Evidence at the Scene of Crime to its examination in the Forensic Science Laboratories, objectively linking the crime with the criminal have not only improved the levels of detection but also enhanced the rate of conviction because of the infallibility of physical/clue/material evidence.