Every criminal investigation revolves around the truth: in order to deliver justice, it is important to find out what truly happened as well as how and why it might have occurred.
Motor vehicle thefts are becoming increasingly elaborate manoeuvres. The true identity of a vehicle is determined largely by its Vehicle Identification Number (VIN) or in some cases, the Chassis Number. Much like a fingerprint, the VIN/Chassis Number is unique to the vehicle and is used by government titling and registration authorities to issue ownership. As such, the VIN/Chassis Number typically plays a key role in investigating vehicle thefts; surely it would be easy to identify perpetrators involved in vehicle theft simply by observing the VIN/Chassis Number to track the registered owner? The answer is both yes and no…
Just as criminals establish false alibis to avoid suspicion, vehicle thieves are capable of erasing and/or disguising a vehicle’s VIN/Chassis Number so its owner cannot be traced. Fortunately, as vehicle thefts continue to evolve, we continue to see significant advancement in the methods used by forensic scientists to combat such crimes. Chemical etching is one such technique used to restore and verify erased VIN/Chassis Numbers.
To all the Harry Potter fans out there, think of the alteration of the VIN/Chassis Number as the polyjuice potion used by thieves and criminals to avoid identification. Chemical etching is –quite literally– the “Thief’s Downfall” which removes all concealments and reveals the vehicle’s true identity.
Often during vehicle thefts, the original VIN/Chassis Number is filed away and over-stamped with a new one. Stamping a VIN/Chassis Number into the chassis compresses the metal resulting in a deformation known as cold working. Cold working increases the metal’s hardness and increases its resistance to oxidation and acid corrosion. In chemical etching, an etching reagent (usually containing a dilute acid in a solvent such as water or alcohol) is applied onto the metal surface. Since the deformed part is more susceptible to acids, it will react more readily than the surrounding area and will be etched away to reveal the original identification marks. These marks, which appear behind the observed (altered) VIN/Chassis Number, are –rather fittingly– known as ghost marks.
If you’ve watched Bosch on Amazon Prime, Line of Duty on BBC One or similar criminal investigation series on other streaming platforms, you will understand the pivotal role that forensic investigation plays in solving any crime. Be it with a fugitive on the run, a terrorist activity, an organised crime or a petty thief trying to make a quick buck, vehicle theft and subsequent efforts to cover one’s tracks is quite commonplace.
Consider this case…A midnight black Toyota Highlander bearing the registration number XX-1234X was reported missing. An investigation team found a Toyota Highlander bearing the same registration number undergoing maintenance in a workshop. A forensic team was called upon to investigate the case. The observed Chassis Number matched the one in the Vehicle Registration Card. Nevertheless, verification of the Chassis Number was imperative.
Following a physical examination, six (6) cycles of chemical etching were conducted and eventually ghost marks emerged behind all the alphanumeric characters of the observed Chassis Number. The true Chassis Number was revealed to be different from the observed one and it was evident that the Chassis Number had been tampered with.
Video 1: Chassis Number before and after chemical etching was conducted. Chassis Number after 6 cycles of chemical etching was conducted. Ghost marks reveal 0025376 behind the originally observed 0069718 (00:48 seconds on the video).
Proof that the Chassis Number had likely been altered during vehicle theft would have enabled the investigation team to determine a suitable outcome and enforce any consequent legal action regarding the case. Thus, forensic investigation is undeniably paramount in reconstructing a criminal incident and identifying the bigger picture, thereby enabling the criminal justice system to function effectively.