Objectives Deviant burials can reveal important information about both social and individual identity, particularly when the mortuary record is supplemented by an examination of skeletal remains. At the postmedieval (17th to 18th c. AD) cemetery of Drawsko (Site 1), Poland, six individuals (of n = 285) received deviant, anti‐vampiristic mortuary treatment. A previous study using radiogenic strontium isotope ratios ( x¯= 0.7112 ± 0.0006, 1σ, n = 60) found that these “vampires” were in fact locals, not migrants to the region targeted for deviant burial due to their status as immigrant outsiders. However, considerable geologic overlap in strontium isotope ratios across the North European Plain may have masked the identification of at least some nonlocal individuals. This study further contextualizes strontium isotope ratios using additional biogeochemical data to test the hypothesis that additional nonlocals were present in the Drawsko cemetery. Methods Stable oxygen and carbon isotopes from the dental enamel of 58 individuals interred in both normative and atypical burials at Drawsko were analyzed. Results Both δ18Oc(VPDB) ( x¯= −4.5 ± 0.7‰) and δ13Cap isotope values ( x¯= −13.6 ± 0.8‰) displayed little variability and were not significantly different between vampire and normative burials, supporting prior strontium results of a largely local population. Nevertheless, homogeneity in oxygen isotope values across other northern European sites makes it difficult to speculate about isotopic regional diversity, leaving open the possibility that additional migrants to the region remain undetected. Additionally, carbon isotope values point to a locally sourced diet dominated by C3 resources but with some supplementation by C4 goods that likely included millet, fitting with historic descriptions of postmedieval diet in Poland. Conclusions Those interred as vampires appear local to the region and thus likely underwent deviant funerary treatment due to some other social stigma not apparent from the skeleton.