In The Unusual Suspect: The Rise and Fall of a Modern-Day Outlaw (Ballantine, Jan.), Machell explores the life of a unique criminal.

How did you first hear about Stephen Jackley?

I came across a short q&a with Stephen in which his crimes and motivations were detailed. I had about a million questions to ask him, which is only natural when you’ve just discovered that a socially isolated geography student from rural England with undiagnosed Asperger’s attempted a string of bank heists during the financial crisis in order to strike back against global income inequality, and that he ultimately ended up in solitary confinement in a U.S. federal prison. I managed to persuade him to let me profile him.

What was most surprising?

That Stephen managed to get so far. It seemed incredible to me that somebody with no prior criminal experience or accomplices could carry out so many crimes and not have the police ever come anywhere close to capturing them. This isn’t an indictment of the British detectives pursuing him. In many ways, they did everything right, other than alight on the highly remote possibility that a young student might also be an armed bank robber.

Do you believe that he was motivated by idealism?

If Stephen didn’t have a long-standing and intense concern for the planet and its people, he would never have found himself going down the path he did. His diaries all make repeated references to the damage being done by global income inequality, of undiluted capitalism, and of the great confidence trick that is money. That said, what also becomes clear is that, as he begins to carry out his crimes, he enjoys the sense of importance that comes with being a wanted man, and of the feeling of control that planning and executing these heists bestowed.

What if he’d been diagnosed earlier?

It’s hard to know. One of the things I’ve tried to emphasize in the book is that Stephen didn’t carry out these crimes simply because he had Asperger’s. The factors which led him to start robbing banks were complex, and include the damage done by his chaotic home life, his resulting social phobia, as well as his own personality and views of the world. It’s important to note that Stephen did receive a good deal of psychiatric support as a child, on account of his parents’ illnesses and his own difficulties with school, so it’s not like he slipped through the cracks of society. It was clear from a young age that Stephen was vulnerable and different, and he still went on to do what he did.