Assessing the impact of Melendez-Diaz on the investigation and prosecution of biological weapons incidents

Document Type

Journal Article

Publication Date



Biosecurity and Bioterrorism


Volume 7, Issue 4

Inclusive Pages



Bioterrorism--legislation & jurisprudence; Certification--legislation & jurisprudence; Expert Testimony--legislation & jurisprudence; Forensic Sciences--legislation & jurisprudence; Bioterrorism


In June 2009, the U.S. Supreme Court asserted in Melendez-Diaz v Massachusetts that the admission of a laboratory analyst’s certificate to validate forensic evidence against a defendant violated the defendant’s Sixth Amendment Confrontation Clause rights. The Court stated that if a prosecution wished to use forensic science evidence against a defendant, the plaintiff must ensure that an actual lab analyst could testify live before the court as to the nature of the laboratory certificate being presented against the defendant, in order to uphold a defendant’s constitutional right to confront the adverse witnesses against him or her. The opinion itself, as well as dicta in both the majority and the dissenting opinions, has potential implications for the success of any future prosecutions of alleged biological weapons use involving microbial forensics. Not only does the Melendez-Diaz opinion create an added burden on laboratory investigators, but the case called into question the reliability of the use of forensic science in the courtroom. Analysts and policymakers should be aware of this ruling and any potential impact the Court may have on the ability to successfully prosecute a biological weapons use event.