Budowle, 2006; Morse and Khan, 2005). Even if evidence strongly supports the hypothesis of a deliberate attack, it may still be very difficult to attribute the attack with certainty to those responsible (i.e., attribution). Attempts to resolve the crime will require advanced methods for characterizing microbial agents, as well as a combination of traditional investigation and intelligence gathering activities.
In response to the need to determine the nature of the threat and the source of the weapon and to identify those who perpetrated the crime, the scientific community rose to the occasion beginning in 1996 and developed the field of microbial forensics. Microbial forensics is the scientific discipline dedicated to analyzing evidence from a bioterrorism act, biocrime, hoax, or inadvertent microorganism/toxin release for attribution purposes (Budowle et al., 2003, 2005a; Köser et al., 2012; Morse and Budowle, 2006). Another goal can be to support analysis of potential bioweapons capabilities for counter-proliferation, treaty verification, and/or interdiction. A forensics investigation initially will attempt to determine the identity of the causal agent and/or source of the bioweapon in much the same manner as in an epidemiological investigation. The epidemiological concerns are identification and characterization of specific disease-causing pathogens or their toxins, their modes of transmission, and any manipulations that may have been performed intentionally to increase their effects against human, animal, or plant targets (Morse and Budowle, 2006; Morse and Khan, 2005). A microbial forensics investigation proceeds further in that evidence is characterized to assist in determining the specific source of the sample, as individualizing as possible, and the methods, means, processes, and locations involved to determine the identity of the perpetrator(s) of the attack or to determine that an act is in preparation. A systems analysis may be able to determine the processes used to generate the weapon or how it was delivered, which also can help inform the investigation and attribution decision. The ultimate goal is attribution—to identify the perpetrator(s) or to reduce the potential perpetrator population to as few individuals as possible so investigative and intelligence methods can be effectively and efficiently applied to “build the case” (Figure A1-1).
Microbial forensic evidence may include the microbe, toxin, nucleic acids, protein signatures, inadvertent microbial contaminants, stabilizers, additives, dispersal devices, and indications of the methods used in a preparation. In addition, traditional types of forensic evidence may be informative and should be part of the toolbox of potential analyses of evidence from an act of bioterrorism or biocrime. Traditional evidence includes fingerprints, body fluids and tissues, hair, fibers, documents, photos, digital evidence, videos, firearms, glass, metals, plastics, paint, powders, explosives, tool marks, and soil. Other types of relevant