Written by a trained examiner.

I have been doing investigations and interrogations since 1992. The deep secrets that people have tried to hide from me and other interrogators and the unique ways in which we eventually got the truth never stops amazing me. I started my career as a detective dealing with predominantly violent crimes. With violent crimes came hardened criminals. The ones, not every detective could get to “crack”…


Over the years I have seen detectives using all sorts of tricks and manoeuvres to crack these hardened criminals. The success rate stayed predominantly low. I had the privilege of being part of one of the task teams established by the then Peninsula Murder and Robbery Unit. The guys almost every criminal feared… Not many hardened criminals enjoyed their stay at the offices of the Murder and Robbery Unit, which was in Kasselvlei Road, Bellville South. – This is the days before the SAPS became a “service” and lost their best investigators to the private sector… – In short, I had the privilege of working with some of the best of the best. I have seen interrogation techniques and tricks which I did not know exist. As an early twenties detective, I got exposed to the art of interrogations. Now many old-school people may think that this involved only violence. On the contrary, this is where you had to interrogate criminals and outsmart them with smart techniques and tricks. I remember the then commander of the unit, who later died in a motor vehicle accident in later years, on one occasion whilst making “potjiekos” (now this would be a hint to the people who worked with him) said that the future of interrogations laid in outsmarting manoeuvres rather than relying on intimidation alone. Many of the old school detectives thought he was crazy. Luckily, I took note of his remarks and made it my business to understand humans.
I started a journey where I read everything possible on human behaviour, deception, and interrogations. – After I left the SAPS to get involved in Private Investigations, I realised how important interrogation and interviewing manoeuvres were. The intimidation the badge brought was gone and I had to make a mark in a tough industry without having the full force of “the law” behind me.

I was lucky to get an opportunity at Old Mutual Head Office in Pinelands where I provided internal investigation services. This period introduced me to hardcore fraud and embezzlement investigations. A field I did not have as much exposure to during my career in the SAPS. The challenges this brought in interviewing and interrogations was almost a completely new field. I now had to deal with very smart and intelligent offenders. (Not that I am saying that offenders in violent crimes are not intelligent.) To embezzle one person out of a couple of bucks might be something everyone can do. To scam thousands of people out of millions required next-level intelligence. During my Old Mutual days, I got introduced to polygraph testing. I remember the first time that we got someone to do a test. I was waiting in anticipation for this to happen. I don’t know who or what I expected but remember that I was very disappointed when I discovered that the polygraph examiner was neither a former SAPS detective nor a science wizard. He started his career in the security industry and got the opportunity to attend the training in the USA. To cut a long story short I expected to learn something from his interrogation techniques. Something I could use in my career going forward. The absolute anti-climax when he finished testing and told us that he would give the result in the next day or two will remain with me until the day I die. No confession and no further questioning were a serious let-down for me. – When we got the suspects back in two days later, they had the opportunity to intimidate witnesses and the investigation came to s standstill.


In later years I met several examiners who went the extra mile and did some interrogations with me. The late Stephen Ford was one of them. In fact, he is the one who told me all there is to know about polygraph testing. Together in investigations, he did at least 500 tests for me. The problem of having to wait for an answer remained throughout our time together.
What I appreciated was the fact his mere presence allowed me much more manoeuvres when interrogating people. People I interrogated did not know that I was waiting for the result and I was able to convince them that I already had the result and that they failed. This led to a remarkably high success rate and confessions. I humbly believe that we became a highly effective team. The number of clients who made use of our services is a testimony of it. Stephen sadly passed away suddenly, and I was back to square one.
I started using other examiners and had the same frustrations…
I then got introduced to Voice Stress Analysis. To make sure I understood the two systems I started researching the two and found –
• There are predominantly two types of Detection of Deception (DOD) testing.
• What people commonly refer to as polygraph is bio-feedback testing. The other is Voice Stress Analysis.
• The word “polygraph” does not exist. It is made up of two words being “poly” which means many and “graph”, which is referring to the graphs which display information of a few things in testing.
• The technology was developed in the previous century and has not been updated in years.
• The test requires a person (subject) to be connected to several sensors which measure things like blood pressure, heartbeat and breathing.
• The test is done and the examiner will later “score” the results and give a finding of either “deception indicated”, which means the person lied, or “no deception indicated”, which means he/she told the truth.

• A flaw in this method is that the examiner will test throughout the day and when done (normally at the end of a workday) will start scoring. One can only imagine the number of incorrect results caused by fatigue…
• The other system Voice Stress Analysis (VSA) is a system where the person is connected only to earphones and a microphone. The test is done, and the computer software scores the charts. Within seconds after the test is completed the examiner will have the result. – Needless to say, I thought I had my solution, especially after I read that the system was developed by the United States Airforce for the War on Terror, where they needed result immediately.
I saved money for the rather stiff training and licensing fee for the Voice Stress Analysis training and completed it in 2017. I then had the best of both worlds, where I could do my tests whilst interrogating people. As a trained examiner I then started getting requests for just testing. In fact, this soon became a large part of our business.


To my utmost surprise I many times end up at people about to be tested who are as nervous as can be, even though they are innocent and not telling lies. (As someone working as both investigator and examiner, it amazes me that people can fear to undergo a test when there is absolutely no investigation being done. – Considering that most examiners have little to no investigation experience and their interrogation skills is limited to the training they got when doing their examiner training, the chances of them trying to get a confession is slim to none. Over the years it struck me that the fear of the unknown, aided by the professional stern look of the examiner, is causing the stress, rather than anything else. – As part of the training, you are taught to look extremely stern and unapproachable when doing a test.)


What further amazes me, and the reason for this article is the fight between biofeedback (“polygraph”) examiners and Voice Stress Analyses examiners. Now keep in mind I am writing this article as an investigator who also does testing and not purely as an examiner. I keep on getting clients who ask me the question about which system is the most reliable. I have had to defend Voice Stress Analysis ad nauseum. And this is not only because I am a trained examiner, but because I have seen the mistakes made by “polygraph” examiners over the years.
The “polygraph” fraternity’s favourite claim is an article where “independent evaluators” claim that Voice Stress Analysis is as reliable as a “coin-toss”. Almost as if their system had been proven as “100% reliable”. The majority of websites of “polygraph examiners” is claiming that they do not provide Voice Stress Analysis testing because it is as reliable as a “coin-toss” and they include the article I mentioned earlier. Again dare I mention, as if their system had been proven to be “100% reliable”…


Everyone seems to be forgetting the public reactions in the 80/90’s when “polygraph testing” arrived in South Africa. I am asking what has changed, and frankly, the only thing that seems to have changed is the relationships examiners had built with clients over the years, because their technology has not changed. – I am not going to bore anyone with explaining the power of rugby tickets and paid hunting/fishing trips as marketing tool…


Before the “polygraph examiners” start attacking me, allow me to tell of a very scary incident a few years ago. I got a call from a client who wanted us to handle an investigation. The client is an international business with more than 100 employees. They had everyone polygraph tested and had compiled a list of the possible suspects. I started interrogating the ones who “failed” the polygraph test and soon started getting confessions. The people worked as a small syndicate and the ones who “cracked” started naming their “associates”. One of the names mentioned by three different individuals (let’s call him John) started puzzling me as he had “passed” his test. I contacted the examiner who assured me that the people who implicated John is telling lies. We arranged a round-table meeting where we agreed to question John together. (Now John was a Rastafarian and the Rastafarian community is known to smoke marijuana. I asked John whether he smokes marijuana which he confirmed. In short, he told me that every morning on his way to work he smokes a “joint”.) I then explained to both the client and the other examiner how my test worked and showed them what the results would look like if John fails, and what it would look like if John pass. I then tested John on the same questions the other examiner used, and John failed. The test was repeated twice after that to prove that it was not a fluke. The other examiner then tested John and to our surprise, John passed. Just for the record, John went on to make full disclosure of his involvement in the syndicate’s operation. – Between us, we concluded that the use of cannabis can be an effective way to “beat” a polygraph test. – Now, this is the type of thing that the “polygraph” fraternity would not want their clients to know about…
Clients should consider the following when deciding on who to use (and no, I am not going to badmouth “polygraph” examiners) –


• No matter which system you use, if you are using it as stand-alone evidence, rather do not do any test. – Stand-alone testing should be limited to periodical testing and pre-employment screening. – This does not mean that you need to do an expensive investigation. If you contract a seasoned interrogator to investigate the facts and interrogate the person, combined with a test, you are much safer. Now, this is where examiners and investigators are going to be separated, simply because many examiners are also investigators, but not all examiners (using either system) is investigators.


• If you are only going to be presented with a report (from either system) you are wasting your money. A “failed” test report cannot be used as evidence in disciplinary hearings and the Police would not even read it. You are better off with an investigation report combined with a test report. If you do your research on your possible service provider check their investigation experience rather than which system they using.

• An innocent person with so many attachments attached to them will have increased stress levels. There is a lot of studies being conducted in the USA on false failed reports which were identified as the reason for increased stress levels. – Another thing the “polygraph” fraternity is not telling clients…

So, the next time someone try and convince you that a “polygraph test” (bio-feedback) is more reliable than the “coin-toss” result of Voice Stress Analysis, please ask them to explain the following –

• How Edward Snowden (WikiLeaks) passed TWO polygraph tests…

• How I could identify John as a suspect when he was passed by an examiner with more than 10 years’ experience.

Do not be fooled by good marketing efforts of people and their “scientific proof” of their competitors’ flaws. If pointing out your competitors’ flaws is your only marketing advantage, one should start worrying. How often do you see the big car manufacturers pointing out the flaws of their competitors in their advertisements? You are correct, never. Simply because they believe in their product and focus their marketing on it. Almost like the Voice Stress Analysis fraternity who focus our marketing efforts on our price advantage and quicker results…