For over thirty years, FBI experts testified about comparative bullet lead analysis (CBLA), a technique that was first used in the investigation into President Kennedy’s assassination. CBLA compares trace chemicals found in bullets at crime scenes with ammunition found in the possession of a suspect. This technique was used by the FBI when firearms (“ballistics”) identification could not be employed – for example, if the weapon was not recovered or the bullet was too mutilated to compare striations. Although the FBI eventually ceased using CBLA, the Bureau’s conduct in first employing the technique and then defending it after it was challenged provides an invaluable insight into how forensic science sometimes works.


Comparative Bullet Lead Analysis, William Tobin, FBI, Scientific Evidence, National Academy of Sciences, Expert Testimony, Criminal Law

Publication Date


Document Type


Place of Original Publication

Criminal Law Bulletin

Publication Information

47 Criminal Law Bulletin 306 (2010)


COinS Paul C. Giannelli Faculty Bio