Validating the Efficacy of archival microclimate proxies for indoor postmortem interval Estimation: A case study...

Indoor death scenes challenge defensible estimation of the minimum postmortem interval (PMI_min) because colonization delay, refrigeration, and poorly characterized microclimates often undermine transparency and reproducibility in medicolegal contexts. We report an indoor death investigation from Busan, Republic of Korea, in which post-feeding third-instar larvae of Boettcherisca peregrina (Diptera: Sarcophagidae) provided the principal entomological evidence. Species identity was confirmed by morphology and COI barcoding. Developmental age was estimated using an accumulated degree-hours (ADH)-only framework parameterized with species-specific constants (developmental zero, D₀ = 10.87 °C). Larval thermal exposure was reconstructed using an archival indoor May temperature proxy (mean = 23.2 °C), with a ± 1 °C sensitivity envelope propagated across all calculations to reflect plausible room-scale variability. The body was removed from the scene on 16 May 2025 (∼15:00) and stored at ≤ 4 °C until autopsy on 19 May 2025 (09:00), arresting further development; thus, larval age refers exclusively to the pre-removal interval. Back-calculation from wandering-phase thresholds yielded a PMI_min of 3.1-8.3 days across the ± 1 °C range. Expressed as calendar bounds, larviposition was estimated between 08 May 2025 (∼21:00) and 13 May 2025 (∼03:00 KST), with a nominal estimate of 09 May (∼12:00) to 11 May (∼01:00 KST) at 23.2 °C. These estimates are coherent with independent administrative anchors and the documented discovery-transfer-autopsy timeline. This report provides a reproducible workflow for indoor PMI_min estimation that explicitly separates pre-removal development from refrigeration arrest and propagates indoor thermal uncertainty, thereby improving transparency and courtroom defensibility in constrained indoor scenes.