Key Pathway Analysis

Certain arson and auto theft investigators have used a technique called key pathway analysis that reportedly allows the determination of which key was last used in a lock. It requires that the lock in question (door lock or ignition lock), and all the keys that exist for use in that lock be sent to a laboratory for examination. Analysis of the lock and key components can potentially be used to determine whether a particular key was used to operate the lock and whether there was any tampering. Key pathway analysis is based on microscopic examination of tool marks left by the metal key against the lock mechanism in a manner analogous to matching striations on bullets to identify the barrel from which they were fired. The method has apparently been accepted for presentation in trial though questions remain among professionals regarding the acceptance of the method and the reliability of some of the conclusions. The analysis is not always conclusive and may not be possible after a fire.