Neuroscientist James Fallon recounts in his new book, “The Psychopath Inside,” the story of how the University of California researcher came to the startling conclusion in 2005 while reviewing PET scans of murderers, schizophrenics, depressives, along with other, normal brains.

Specifically, Fallon was looking at the scans to learn about the functionality of areas of the brain linked to empathy, morality and self-control. In psychopaths, he believed these areas exhibited little activity.

“I was also doing a study on Alzheimer’s and as part of that, had brain scans from me and everyone in my family right on my desk,” Fallon told Smithsonian Magazine. “I got to the bottom of the stack, and saw this scan that was obviously pathological.”

The scan, it turns out, was of his own brain.

Fallon double-checked his laboratory’s PET machine, but was unable to find any malfunctions.

“I’ve never killed anybody, or raped anyone,” Fallon told Smithsonian Magazine. So the first thing I thought was that maybe my hypothesis was wrong, and that these brain areas are not reflective of psychopathy or murderous behavior.”

But then the pieces slowly began falling into place, Fox News reports.

Fallon is reportedly related to seven alleged murderers, including Lizzie Borden, tried and acquitted of killing her father and stepmother in Massachusetts in 1892.

Оne of Fallons’s great-grandfathers, Thomas Cornell, was hanged more than 300 years ago in the then-American colonies for murdering his mother.

 “I had all these high-risk alleles for aggression, violence and low empathy,” Fallon told Smithsonian.

 “But while I’m aggressive...my aggression is sublimated. I’d rather beat someone in an argument than beat them up.”

 “I was loved, and that protected me”.