SEATTLE -- Science is becoming a more important part of catching a killer or terrorist and keeping the innocent out of jail.
A Seattle neuroscientist is leading the way with technology based on a simple fact: your brain can't lie.
An odd looking headband, flashing words on a computer screen, and a couple clicks of a mouse could be the secret to putting a murderer behind bars.
"It's a game changer in the field of global security," said Dr. Larry Farwell, Chairman of Brain Fingerprinting Labs who developed "brain fingerprinting" - a lie detector test for the 21st century.
While polygraph tests rely on emotional responses, brain fingerprinting records how your brain reacts to words and images related to a crime -- ones only the killer would recognize.
"If the person was there, they get 'ah ha!' response in the brain waves," he said. "The brain says 'Ah ha!' "
And that "ah ha" moment can't be covered up.
"This is an involuntary response that happens very quickly; it's not something you can control," he said.
Dr. Farwell has worked with the CIA, FBI and law enforcement agencies around the country. His cases include an innocent Iowa man finally freed after 23 years, and a serial killer in Missouri who eventually confessed.
It's technology Farwell says is fool proof. And unlike polygraphs, these can be admitted in court.
There's still resistance from some law enforcement agencies.
"It took some time, it always takes time," Farwell said. "It took time for fingerprints, for DNA and now for brain fingerprinting."
But Dr. Farwell says his guarantee will help more people accept it.
"I can't beat it, and I invented it."
He has even offered $100,000 to anyone who can fool the system, and so far nobody has.