Forensic Authentication of Digital Audio Recordings
Bruce E. Koenig, Douglas S. Lacey · Journal of the Audio Engineering Society · 2009
A detailed methodology is described to authenticate investigative and other forensic audio recordings collected via digital recording systems. These examinations are conducted to determine whether the recorded information is original, contains alterations, has discontinuities due to recorder stops and starts, and matches a submitted recording system, if available. Sections are included on examination requests, laboratory space, contributor-supplied materials, equipment and software, an 11-step authenticity examination protocol, authenticity examples, evidence handling, and expert testimony. The 11-step protocol consists of evidence marking, physical inspection, digital data imaging and playback optimization, critical listening, high-resolution waveform analysis, narrow-band spectrum analysis, spectrographic analysis, digital data analysis, miscellaneous techniques, work notes, and reporting. A formal procedure has been developed to optimally authenticate digital recordings submitted to a forensic laboratory, based on proper education, training, specialized schooling, and experience ; appropriate laboratory space; specialized software; scientific protocols; accepted evidence-handling practices; and effective expert testimony. The paper complements an earlier publication (1990) except that it does not present specific procedures of a particular government laboratory.