Military Defense Investigation Knowledge Base
Military Defense Investigation Authority Publication
Authority Publication No. DI-128
Toxicology Evidence in Alcohol- and Drug-Related Cases: Timing, Dosage, and Alternative Explanations
Independent Military Defense Investigations
Supporting Attorneys, Service Members, and Families
Publication Date: August 24, 2026
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Executive Summary
Toxicology evidence in military investigations should be evaluated by connecting specimen collection and laboratory results to timing, dosage, pharmacology, impairment, and alternative explanations.
A toxicology result may provide important evidence in an alcohol- or drug-related military case, but the reported value does not automatically establish the level, dosage, or degree of impairment that existed at an earlier event.
DI-128 explains how defense investigators can connect specimen type and collection time with seals, transport, storage, screening and confirmation methods, calibration, controls, analytical uncertainty, medication and exposure history, and the event timeline.
The publication also addresses qualified retrograde or pharmacological analysis. In its practical example, a blood result is treated as the level at an earlier event; the defense instead documents drinking and collection times and asks a qualified toxicologist whether a reliable backward estimate is possible.
The purpose is not to reject laboratory evidence automatically. It is to preserve the original sources, reconstruct chronology and method, distinguish the measured result from later inference, and accurately state what the available toxicology does and does not establish.
DI-128 explains how defense investigators evaluate toxicology evidence by reconstructing specimen collection, laboratory methods, event timing, exposure history, and qualified analysis before drawing conclusions about dosage or impairment.
Who Should Read This Publication?
Military Defense Counsel
Use the specimen and event chronology, laboratory source record, and documented limitations to identify issues requiring additional discovery, expert consultation, evidentiary analysis, or litigation strategy.
Defense Investigators
Preserve specimen and laboratory records, reconstruct collection and event timing, document medications and exposure history, identify analytical methods and uncertainty, and trace toxicology conclusions back to sources.
Service Members
Understand why a later alcohol or drug test result may not automatically establish the level or degree of impairment that existed at the time of an earlier alleged event.
Qualified Toxicology or Pharmacology Experts
Review complete specimen, laboratory, timing, exposure, and analytical records and clearly defined questions concerning interpretation, retrograde analysis, pharmacology, dosage, or impairment when counsel requests expert review.
Families
Understand why preserving timelines, medication information, receipts, communications, and other relevant records may matter, while leaving toxicological interpretation and investigative decisions to counsel, investigators, and qualified experts.
Companion Video
This companion video expands on the investigative concepts presented in this Authority Publication through additional explanation, practical examples, and professional investigative insight.
About Michael West
The investigative guidance presented throughout these Authority Publications is based upon decades of professional experience conducting military, federal, criminal, civil, and private investigations. The principles discussed in these publications are drawn from real investigative work involving complex cases, witness development, evidence analysis, and factual case preparation.
Michael West has served as a Special Agent with the United States Air Force Office of Special Investigations (AFOSI) and the Department of Defense Inspector General, conducted federal background investigations, and spent decades working as a licensed private investigator supporting attorneys, businesses, service members, and private clients. Throughout his career, his work has focused on identifying facts, locating witnesses, analyzing evidence, and strengthening the factual foundation of legal cases through independent investigation.
The Military Defense Investigation Knowledge Base was created to share that investigative experience in a practical, understandable format. Its purpose is to help attorneys, service members, and families better understand the investigative process, ask more informed questions, and recognize opportunities where independent investigation may strengthen the defense.
Important Information
This Authority Publication is provided for educational and informational purposes and is intended to help readers better understand military defense investigations and the investigative process. It is based upon professional investigative experience and is designed to provide practical investigative insight rather than legal advice.
Every military case is unique. The investigative strategies, factual issues, and legal considerations applicable to one case may not apply to another. Readers should consult with a qualified attorney regarding legal rights, legal strategy, and decisions involving their individual circumstances.
Nothing contained in this publication should be interpreted as creating an attorney-client relationship or an investigator-client relationship. References to investigative techniques, procedures, or case examples are provided solely to illustrate investigative principles and should not be considered legal guidance.
Effective military defense is strengthened by informed legal representation supported by thorough factual investigation. The purpose of these Authority Publications is to help readers better understand that investigative process so they can communicate more effectively with qualified legal counsel and make informed decisions throughout the military justice process.