One of the many ways missing person cold cases are solved (other than through Doe Network volunteers) is through the FBI’s biometric analysis services that also includes the Combined DNA Index System (
CODIS).
The Combined DNA Index System, or CODIS, blends forensic science and computer technology into a tool that enables federal, state, and local forensic laboratories to exchange and compare DNA profiles electronically, thereby linking serial violent crimes to each other and to known offenders.
In the case below, William Herman Hietamaki went missing in 1995. Fourteen years later, November 2009, two workers pouring cement near the Hoover Dam found some bones that were determined to be human. A search of the area turned up more bones, but identifying the body wasn't easy because the whole process itself was very complicated and very expensive, and also very interesting (at least to anyone interested in using forensics to solve missing person cold cases anyway), although, because of the condition of the bones they couldn't determine how the man died.
The following article can explain the whole process a whole lot better than I ever could:
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