VSA Tech

Covert Capabilities of Voice Stress Examinations

Covert Capabilities of Voice Stress Examinations

by Al Hall, Owner, TVCA Verifying Truth December 2023


As we know, Truth Verification (i.e. Lie detection) has been around for centuries. And in many arenas lie detection has been considered the second oldest profession. Thus, when war, politics, crime and business became more spiteful and competitive, truthful information was highly sought after in having the upper hand over one’s competitor(s). Over time, many technological advances enhanced identifying lying and deception specifically through Voice Stress Analyzer (VSA) instruments, Polygraph equipment, and a myriad of other voice stress analyzer companies which provide Lie Detection/Truth and Deception services and equipment. (A list upon request.)

So why conduct covert VSA Examinations? Simple, to unwittingly elicit information from a source to asses and validate the information to determine truth or deception. Law Enforcement (LE) agencies for example (Police, Sherriff, Border Patrol, to mention a few) use voice stress technology for several types of investigations/examinations. Vetting a Confidential Informant (CI) and validating critical information is paramount to successful Law Enforcement operations and this is just one example of many. VSA technology has been instrumental in assisting LE in solving crimes for decades. This article provides particulars on managing proper questions, recording and conducting covert VSA examinations. This article is meant as an introduction to and a basic review of covert VSA examinations outlined in more detail in VSA operating manuals.

The Basics

A covert examination will always be recorded, and processed later through a voice stress analyzer. A covert voice stress examination will be structured so that it becomes part of the (8)conversation between the person recording it and the unwitting subject of the recording. Keeping in mind the purpose of the covert examination is to conduct it in such a way that the subject has no knowledge they are being recorded or tested. The voice stress examiner is only limited by their imagination when it comes to how they obtain their recording of the interview with the subject.

Keep in mind, the more specific and structured the conversation is with the subject, the greater the accuracy of the voice stress analysis of the recorded interview.

Common Issues

Using a telephone or Voice Over Internet Protocol (VOIP) on a computer often does not allow for the examiner to observe the subject as they respond to the questions asked.

When using a recording device (not over the phone), not having it close enough to the subject to obtain a suitable recording. If there are volume problems with the recording, it may not be suitable to analyze.

Background noise can, and sometimes does, adversely affect recordings. If the background noise is of greater volume than the voice of the subject, the recording may not be suitable for voice stress analysis.

Avoid Problem Questions a) Questions that are redundant. b) Questions that are vague. c) Questions that circumvent the issue. d) Questions that contain multiple issues. e) Examinations with too many questions.

Basic Considerations a) Use a good reliable recorder. b) Consider the recording capacity of the recorder being used. c) If recording in person, consider the placement location of the recorder. d) If recording over the phone or by voice over internet protocol, be cognizant to whether the subject is speaking loud enough. Don’t hesitate to ask the subject to speak louder, stating you are having problems hearing them.

Practice, Practice, Practice

Chances are you will most likely only get one opportunity to obtain the recording you need. Practicing how you plan to obtain the recording, and what questions you will be asking will improve your odds at obtaining a quality recording which can then capture VSA patterns for evaluation. Remember, your voice stress analysis will only be as good as the recording you obtain; identifying and capturing the single yes or no voice pattern within the recording can also be challenging. Practice as well as patience is the necessary evil in becoming proficient at capturing patterns from a recording. (9)

The Summary Stage

The voice stress examiner must always begin with a structured format that starts with two irrelevant questions, then continues with the relevant & irrelevant sequence format for the questions needed to be answered. Remember to keep the relevant questions to a minimum, as too many questions can result in de-sensitization of the Subject skewing the results of the test. Always start with the secondary question, followed by the primary question. And to help elicit a “YES” or “NO” response to the test questions, use “is that correct?” at the end of your question. Remember that capturing the patterns require a Yes or No answer to be evaluated on your VSA instrument.

The Second Chart

Remember that you will need to run a second chart, just as you would do for a normal overt exam. This is because of the situational stress that will undoubtedly be on the first chart. For this reason, you will need to ask the same questions again from the unwitting subject. Telling the unwitting subject that you want to make sure you heard them correctly, you would like to go over the questions you just asked them. In most cases the subject will not object. Now it is just a matter of going through the question again with the subject. This works with both unwitting subjects that know you are officially questioning them, and with those that you have not disclosed your true identity to.3,4,5

3 Hall, A.G. (2023, October 31); Curriculum vitae. 4 Martin, R., Hughes, D., & Rice, L.; (2016); VIPRE Voice Stress Training Manual; VIPRE Technology Group, LLC, Orlando, Florida. 5 CVSA II Computer Voice Stress Analyzer: Operating Manual; NITV FS, LLC West Palm Beach, Florida.

Conducting Covert VSA Examination

Example of a covert exam, questions for recording a covert telephonic conversation and sample patterns captured from the VSA machine for analysis and evaluation. IR - Your name is John Doe, correct? IR - I’ve got your address as 123 Any Street. Is that correct? R - John will have the drugs with him when he meets us, correct? IR - I've got your cell phone number as 987-654-321. Is that correct? R - Does John plan on robbing us when we show up to buy drugs from him? IR - You’re still living with your parents, correct?

Using audio software, e.g., Audacity in conjunction with the VSA computer, Yes and No patterns can be captured and analyzed.

Sample of a voice recording from a phone conversation, used in a covert VSA exam:

The latest version of Audacity audio software was used to capture the aforementioned phone conversation. Audacity is free to download and use.

About the Author

Al Hall retired from the United States Army and Defense Intelligence Agency (DIA) as a Senior Intelligence Officer with over 25 years’ experience and with over a decade of Voice Stress Analysis (VSA) expertise. Primarily serving overseas in Europe, Asia, Near East and Africa, Al brings a wealth of experience to the voice stress industry in the disciplines of Human Intelligence (HUMINT), Strategic Debriefing/Interviewing, as well as Human Resource Management, Training Development and Program Management. Additionally, Al worked extensively with German Federal and State Law Enforcement Agencies for over five years focused on Counter Terrorism and Counterintelligence operations – and earned a trusted status with his German police counterparts. Al earned a Bachelor of Science Degree from the University of Maryland, is an honorary member of the German Special Forces Police Commandos, and is a Certified Voice Stress Examiner with 10 plus years’ experience.



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