Mason doesn't try to conceal that he was motivated by class envy. "I was a poor boy brought up in West Virginia. My mother was very straight-laced and taught me morality. My father was moral too. But it didn't rub off on me too much. When our family moved to a wealthy apartment complex in Cleveland, Ohio, I developed an animosity towards those people. I was the only child and they were always giving me orders."

When setting out to steal from the rich he was careful not to think about the misery he would cause them. "I had to stay distanced. I had to keep them in the category of objects, not human beings. And that was mostly easy because so many of them were so ostentatious. I certainly had no morality about wealthy people who flaunted their jewellery."

Sometimes he succumbed to sentimentality. "Carol Channing was so sweet and nice that I couldn't do it to her. And in Palm Beach there was this couple I had my eye on, but they were in the paper talking about their 50th wedding anniversary and they came over all lovey-dovey and I thought, drop it, just drop it."