Case Study 5: Spiked Drink

Laced or spiked drink cases (“back calculations”): Were the individual’s drinks unknowingly laced with additional alcohol?

Situation…The Defendant was charged with Driving with Excess Alcohol but reported that he had knowingly consumed only two pints of Stella Artois lager.

However, it was suggested by a witness that the defendant had also unwittingly consumed about 100ml of vodka in the form of laced or spiked drink.

Action…

Bericon Forensics was asked to undertake calculations using the supplied data and try to establish whether the Defendant’s account could be correct and, more importantly, determine what their reading would have been at the time of driving.

Result…

A forward calculation showed that without the contribution of any laced alcohol, the Defendant would have had a blood alcohol concentration below the statutory limit at the time of driving.

This possibility was further supported in other calculations (“back- calculations”) which showed that their consumption of the stated quantities of lager and vodka could account for the reading. Additionally this would also mean that at the time of driving their reading would have been below the statutory limit if the defendant had not unwittingly consumed the laced or spiked drink.

The Magistrates found the Defendant Not Guilty.