ABSTRACT
The polygraph, more commonly referred to as the lie detector, is another excellent tool available to the cold case investigator that cannot be overlooked or forgotten. In cold case homicide investigations, the polygraph can play a valuable role in assisting and assessing a person’s knowledge of or involvement in a case under investigation. In addition, review of cold case files may reveal that subjects involved in the unsolved case had been polygraphed in decades past (see Figure 29.1). Have an examiner review the polygraph charts. Techniques and equipment have changed. Do not assume that the examiner will agree on the earlier conclusions. If the subject is available, and he is a possible suspect or have valuable information for your investigation, he should probably be retested. The revived investigation could have produced some new information and questions that now need to be addressed. Sometimes individuals will take a private polygraph examination. Again, do not assume the results are accurate. The information provided to the examiner about the case came from the individual who was tested and could have been inaccurate, which would have played a significant role in the results of the test. The private polygraph examiner will be happy to produce his polygraph file for your review as long as it does not violate any attorney–client privilege.
