of constant threats or to serve their time in highly restrictive, protective custody units but mark higgins takes a different approach. >> my crime is a serial rapist. i was convicted of several different charges, rape, attempted rape, nine asserted counts in all for a total of 35 years. >> we met higgins at the river bend maximum security institution in tennessee. on the outside, he had a professional career and lived in a wealthy nashville suburb with his wife and four churn. four children. he lived a secretive double life. as he carried out his string of attacks between 1909 and '95, the media dubbed him the gentleman rapist. >> the feeling we had on the crew is, wow, that guy is scary. he didn't appear dangerous or your stereotypical inmate but you know, i think that's what made him really scary was that he was like your neighbor. the president of your city council or your best friend. i think that made it all the more creepy. >> rapists such as myself, pedophiles, people that murder children or women, they're at the bottom of that pecking order. okay? and there's a lot of men that will