Dr. Lemos is an award-winning, board-certified forensic toxicologist with experience in the determination and interpretation of alcohol, drugs and poisons in biological fluids and matrices as well as their interactions and effects in both postmortem toxicology cases as well as human performance toxicology cases.

Dr. Lemos' formal education includes:

Bachelor of Science in Criminalistics (State University of New York, USA, 1993)

Master of Science in Forensic Science (John Jay College of Criminal Justice, USA, 1996)

Doctorate in Forensic Medicine and Science (University of Glasgow, UK, 1999)

Currently, Dr. Lemos holds the following appointments:

Director, Forensic Laboratory Division, Office of the Chief Medical Examiner, City and County of San Francisco

Chief Forensic Toxicologist, Forensic Laboratory Division, Office of the Chief Medical Examiner, City and County of San Francisco

Examiner, Postgraduate Diploma in Forensic Human Identification, The Worshipful Society of the Apothecaries of London.

Clinical Professor (WOS), Department of Laboratory Medicine, School of Medicine, University of California, San Francisco.

Dr. Lemos has testified on more than 250 occasions as an expert witness in response to requests from both the prosecution as well as the defense in the United Kingdom and the United States of America for more than a decade.

He has consulted on and testified in cases pertaining to medico-legal death investigations, accidental deaths, officer-involved deaths, homicides, as well as in drug-facilitated sexual assaults, hit-and-run offenses, driving under the influence offenses, public intoxication offenses and several other types of offenses.

He has been qualified as an expert in forensic science, forensic toxicology, postmortem forensic toxicology, human performance forensic toxicology, on the effects and interactions of alcohol and drugs on human behavior and on the interpretation of drug and alcohol concentrations in blood, urine, hair and other tissues.

Dr. Lemos remains active in all aspects of forensic toxicology and is currently affiliated with the following professional organisations and societies:

• Fellow, Royal Society of Chemistry
• Fellow, American Academy of Forensic Sciences
• Member, The International Association of Forensic Toxicologists
• Member, Society of Forensic Toxicologists
• Member, British Academy of Forensic Sciences
• Member, California Association of Toxicologists
• Member, California Association of Criminalists
• Member, American Chemical Society
• Member, American Society of Crime Laboratory Directors
• Affiliate Member, National Association of Medical Examiners

Dr. Lemos is often invited to be a peer reviewer for various scientific journals in forensic sciences including Medicine, Science and the Law, Journal of Forensic and Legal Medicine, Science and Justice, the Journal of Forensic Sciences, Forensic Science International, Journal of Forensic Science and Criminology, and the Journal of Analytical Toxicology.

Since 2011, Dr. Lemos  is a Diplomate of the American Board of Forensic Toxicology (D-ABFT).