The scientist who theorized that when a criminal came into contact with another object or person, a cross-transference of evidence could occur

• A. Edmond Locard
• B. Calvin Goddard
• C. Alphonse Bertillon
• D. Sir John Fielding

Answer: (A)

The central idea being tested is Locard's Exchange Principle: whenever two objects or people come into contact, materials are transferred between them. This cross-transfer explains why investigators search for trace evidence—tiny amounts of fibers, skin cells, dust, or residues can move from a suspect to a scene or from a scene to a suspect even when nothing obvious is visible. Edmond Locard formulated this concept, laying the foundation for how trace evidence is understood and collected in forensic investigations. The other figures contributed in other forensic areas—Calvin Goddard advanced firearm identification, Alphonse Bertillon developed the anthropometric system for identification, and Sir John Fielding was an early magistrate and investigator—so they don’t describe the idea of evidence transfer upon contact.