J. Robert Zettl

Mr. Zettl (BS, MPA/FAAFS) received his undergraduate degree from Pittsburg State University in Kansas and a Masters in Public Administration from the University of Colorado. Mr. Zettl has been actively employed in the field of forensic science for over 50 years and in his last full time employment supervised the Toxicology Program for the State of Colorado with emphasis on blood/urine drug analysis and breath alcohol certification and training. His specific areas of interest are drug and alcohol analytical procedures, instrumentation used for biological specimens as well as Laboratory Quality Assurance procedures, SFST’s & DRE to determine drug and alcohol impairment and the uncertainty of measurement of procedures used for blood, urine and breath alcohol testing.

Mr. Zettl is a Fellow of the American Academy of Forensic Sciences, member and past President of the Society of Forensic Toxicologists, and belongs to and is active in numerous other national and international forensic science organizations. Mr. Zettl is an author of several publications in forensic science and continues to provide forensic information at symposiums and lectures at numerous forums on the issues related to drug and alcohol testing procedures and protocols. Mr. Zettl has appeared in hundreds of criminal and civil court cases as well as military justice cases where the issues were the impairing effects of alcohol and other drugs; chemical test process issues, proper use of alcohol and drug test instrumentation; interpretation of test results and the reliability of tests and testing procedures for alcohol and other drugs by blood, urine and breath. Mr. Zettl provides consultation and testimony in criminal and civil matters for governmental agencies, private attorneys, coroners, medical examiners, military courts and the private sector within the United States. Mr. Zettl is an inspector for the National Laboratory Certification Program and is POST certified to provide training for the State of Wyoming Toxicology Program.

Mr. Zettl received the following awards: Borkenstein Award from the National Safety Council, Ray Abernethy Award from the Toxicology Section of the American Academy of Forensic Science and the Local Heroes Award from the State of Colorado.


  • Melendez-Diaz: CDS lab reports (in state appendix)
  • Melendez-Diaz: oral argument transcript
  • Melendez-Diaz v. Massachusetts (decided June 25, 2009)
  • Briscoe: oral argument transcript
  • Briscoe v. Virginia (decided January 25, 2010)
  • Bullcoming: Blood Alcohol Analysis Lab Report (in joint appendix)
  • Bullcoming: oral argument transcript
  • Bullcoming v. New Mexico (decided June 23, 2011)
  • Commonwealth v. Yohe (Pennsylvania Supreme Court 5/7/13)
  • Williams: Cellmark DNA Lab Report
  • Williams: oral argument transcript
  • Williams v. Illinois (decided June 18, 2012)
  • Stuart v. Alabama (dissent from certiorari denial 11/28/18)