In June 2024, CSI AFRICA was contacted by a prominent aviation company that operates local and international aircraft charters. The CEO reported that a small safe, containing a significant amount of local and foreign currency, had been stolen from a cupboard in his office while he was on a business trip abroad. Upon his return, the CEO discovered the safe in the generator room. He wisely preserved the evidence by avoiding contact with the safe, locking the room to prevent unauthorized access, and safeguarding against potential tampering or contamination. Seeking further investigation and the identification of the culprit, the CEO engaged CSI AFRICA’s services.
CSI AFRICA’s polygraph examiners conducted tests over two days on 20 individuals who had access to the office building and, potentially, the stolen money during the CEO’s absence. Of those tested, 17 individuals successfully passed their polygraphs and were immediately excluded from further investigation. The remaining three were questioned further, but no confessions were made at the time.
The CSI AFRICA Forensics team was then called in to collect fingerprints from the safe found in the generator room. Elimination prints were also taken from the three individuals who failed their polygraphs, in an attempt to identify the thief. Two of the individuals were successfully excluded based on their fingerprints, while the third was identified as the culprit through a direct match between his prints and those found on the safe.
When interviewed again, the responsible individual confessed. He admitted to entering the CEO’s office during his absence, removing the safe, and relocating it to the secluded generator room, where he would be less likely to be noticed. Using a cordless angle grinder, he partially cut open the back of the safe to access the money. After taking only the local currency—chosen for its liquidity and ease of use without raising suspicion—he attempted to seal the back of the safe with silicone, hoping to return it to the office before the CEO returned. He explained that while the foreign currency was more valuable, converting it would have required showing his passport and flight details, creating a paper trail that could incriminate him.
Further investigation revealed that the two other individuals who failed the polygraph were the culprit’s biological brother and aunt, both employed by the same company. They had prior knowledge of the theft but chose to remain silent, which caused sufficient cognitive stress to trigger negative physiological reactions during their polygraph tests. This phenomenon, known as “guilty knowledge,” explained their failed results.
The case was subsequently escalated to the South African Police Service (SAPS) for further action, based on forensic evidence (fingerprint match) and corroborating evidence (failed polygraph results).
This case highlights the effectiveness of polygraph testing as an invaluable investigative tool, enabling organizations to save time and resources in uncovering the truth.
