Compose a 1500 words assignment on cold case investigations. Needs to be plagiarism free! Many police organizations have dedicated cold cases units whose only function is to revive these cases and try to solve them. We will try to analyze the investigation of cold cases in this research paper. The primary reason for many police organizations having dedicated Cold case units is the falling clearance rates. Clearance rates can be simply defined as the number of cases solved divided by the total number of cases. The overall homicide clearance rates in the USA has fallen from 91% in 1965 to just 64% in 2008. (Federal Bureau of Investigation, 2009).Due to this tremendous fall in the clearance rates and the advent of new technologies such as DNA convinced investigators that various unsolved cases can now be solved and thus the concept of cold case investigation was born. (C.L, 1997).Many reasons have been cited for the falling clearance rates. Some of them increase in stranger crimes. drug-related activities, lack of witnesses, fear of retaliation among the witness and distrust between police and society have been cited as the main reasons for the declining clearance rates of cases. (Rinehart, 1996). Historically the investigation of a case required a number of witnesses in order to prove that a particular person was present at the crime scene. However, with the advent of DNA testing in the 1980s brought about a major revolution. Initially, DNA was used by investigators in order to strengthen their case against an individual who has already been identified as a suspect but crime experts are now using DNA in order to identify suspects in cases which have gone cold. The federal government has even developed a system of national DNA databases which is called as CODIS(Combined DNA Index System).CODIS can be used by police officers to match DNA at the crime scene against the database and has significantly helped in solving many cases.