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Bloodstain Pattern Analysis: Science Over Advocacy (with Jeremiah “Jeremy” Morris)
Host Angela Tanzillo-Swarts returns to Secrets from the Crime Lab to share a conversation with bloodstain pattern analyst Jeremiah “Jeremy” Morris of the Johnson County Sheriff’s Office Criminalistics Laboratory, discussing “real” BPA, scientific responsibility in courtroom testimony, and the need for measured, objective, science-rooted conclusions. Morris outlines his background and explains the shift from the international SWGSTAIN working group to the U.S.-based OSAC standards process following the 2009 NAS report, including improved education and training standards emphasizing science coursework. They cover challenges with inconsistent BPA methods and terminology, the move toward feature-based classification and decision maps, and Morris’s lab method (DCAP: documentation, classification, analysis, peer review) using linear sequential unmasking to reduce bias. They address major uncertainties in interpreting blood on textiles versus non-porous surfaces, the value of magnification and 3D garment analysis, and the importance of being willing to say “I don’t know.”
00:00 Science Over Advocacy
00:49 Meet the Host and Guest
02:41 Conference on Wrongful Convictions
06:35 NAS Report and Forensic Errors
11:47 Podcast Disclaimer and Kickoff
13:22 Jeremy Morris Background
16:16 SWGSTAIN to OSAC Shift
20:39 NAS Critiques and Training Gaps
23:47 Standards and Science Requirements
30:59 Methods and the DCAP Framework
36:16 Bias Control and Unmasking
37:02 Working Scenes Without Theories
38:52 Standardizing BPA Language
40:20 Why Velocity Terms Mislead
43:04 Mechanism vs Feature Taxonomy
47:44 Future Feature-Based Classification
49:36 Porous vs Nonporous Surfaces
52:52 Textile Uncertainty and Broad Labels
55:00 Criteria for Spatter on Clothing
56:59 Fabric Treatments and Microscopy
01:00:21 3D Garment Analysis in Practice
01:06:12 Answering Junk Science Critiques
01:08:48 Ethics and Responsibility on Stand
01:12:05 Closing Thanks and Event Plug
Links
Bloodstain Conference 18-Nov-2026 at UNT https://www.zeffy.com/en-US/ticketing/bloodstain-pattern-analysis-bpa-in-the-courtroom-cle
OSAC Registry: https://www.nist.gov/osac/registry
2009 NAS Report: https://www.ojp.gov/pdffiles1/nij/grants/228091.pdf
2024 Review Paper on Bloodstain Classification: https://pubmed.ncbi.nlm.nih.gov/39025566/
Books
Handbook on Bloodstain Pattern Analysis
Bloodstain Pattern Analysis with an Introduction to Crime Scene Reconstruction