Guanaco is a protected, widely distributed ungulate in South America. In the case at issue, a poacher, after killing guanacos in Valle Chacabuco, Chilean Patagonia, transported and stored the meat. Samples were retrieved by local police, but the suspect claimed that the meat was from a horse. Mitochondrial cytochrome b gene (774 pb), 15 loci microsatellites, and SRY gene were used to identify the species, number of animals and their population origin, as well as the sex of the animals, respectively. Analysis revealed that the samples came from a female (absence of SRY gene) Patagonian guanaco, clearly distinguishing it from sympatric ungulates. Analysis of the microsatellite set markers amplified for each sample extracted from the evidence showed the presence of the same alleles for each locus. This is strong evidence that the samples taken at the police station corresponded to the same individual, even though the poachers had been observed killing five guanacos. This result is consistent with the mitochondrial (cytochrome b) and sex (SRY) marker sequences that showed a similar pattern of no variation. To the authors' knowledge, this is the first report in which molecular tools were applied in a forensic investigation in solving a wildlife poaching case in Chile and applied to a wild South American camelid. The authors recommend that DNA forensics protocols be linked with management and conservation plans for guanacos protection. In addition to providing an overview of the specific case, descriptions of materials and methods used in this study address specimen collection and species identification, sex determination, and determination of individuals. 1 table and 34 references