ABSTRACT
Consider the totality of the evidence at a crime scene. A mental checklist might include footwear impression evidence, bloodstains, bullets, and so on. All are important, but scene investigators often fail to find one or more, simply assuming that it was not present. This is not unusual and it is expected. For example, ballistics evidence is not expected and should not be present if the crime did not involve a shooting. Failing to locate biological evidence, however, has a different “feel” because of the lofty importance DNA evidence enjoys. Such importance is given to DNA because it can identify someone to the exclusion of everyone in the world. This is why crime scene investigators and scientists often focus on finding biological evidence, so much so that their rallying cry might well be, “Find DNA and you’ve got your perp.” This works because DNA profiles from biological evidence collected at the crime scene are uploaded into an FBI-maintained database-CODIS (the Combined DNA Indexing System). Once in the system, scene profiles can be matched to other crime scenes, convicted felons, arrestees, or to identify the missing persons. It should not come as a surprise that DNA is so coveted from investigational and legal perspectives. There are scenes, however, where investigators fail to find biological evidence. The fact is they missed it.
