A technique called “brain fingerprinting,” which seeks to probe whether a suspect has specific knowledge of a crime, could become a powerful weapon in national security, its inventor believes.

Lawrence Farwell, a Harvard-educated neuroscientist who founded Brain Fingerprinting Laboratories Inc. 12 years ago and runs the company from a small town in southern Iowa, believes the technique could emerge as the next big thing in law enforcement and intelligence.

Brain fingerprinting works by measuring and analyzing split-second spikes in electrical activity in the brain when it responds to something it recognizes.

For example, if a suspected murderer was shown a detail of the crime scene that only he would know, his brain would involuntarily register that knowledge. Under Farwell’s system, that brain activity is picked up through electrodes attached to the suspect’s scalp and measured by an electroencephalograph (EEG) as a waveform.