Professor Lemos is a forensic toxicologist with experience in the determination 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.

Professor 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 & Science (University of Glasgow, UK, 1999)

Professor Lemos has served on numerous occasions as an expert witness for both the prosecution as well as the defence 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 death investigations, drug-facilitated sexual assaults, hit-and-run offences, driving under the influence offences, public intoxication offences and several other types of offences.

He has been qualified as an expert on the effects and interactions of drugs and alcohol on human behaviour and on the interpretation of blood, urine, hair and other tissue drug and alcohol levels both in the United Kingdom and the United States of America.

Professor 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, London Toxicology Group
• Member, British Academy of Forensic Sciences
• Member, California Association of Toxicologists
• Member, American Chemical Society
• Member, American Society of Crime Laboratory Directors

Professor Lemos is often invited to be a peer reviewer for various scientific journals in forensic sciences including The Journal of Clinical Forensic Medicine, Science and Justice, the Journal of Forensic Sciences, and the Journal of Analytical Toxicology.

Since 2003, Professor Lemos is the Science Editor of Medicine, Science and the Law, the official journal of the British Academy of Forensic Sciences.