'Butcher Baker' Prosecutor Frank Rothschild Recalls the 'Transformation' of Serial Killer Robert Hansen in ID Special (Exclusive)

To this day, serial killer Robert Hansen still "haunts" Frank Rothschild, who prosecuted the "Butcher Baker" case back in 1983. While Hansen outwardly presented as a family man, his passion for hunting was proven to be sinister, as he was ultimately convicted of abducting, raping and killing at least 17 women in the Anchorage, Alaska wilderness from 1971 to 1983 and sentenced to 461 years and a life sentence without the possibility of parole.

For the first time, tapes of Hansen's confessions will be heard publicly in the new Investigation Discovery special The Butcher Baker: The Mind of a Monster, premiering Wednesday. Rothschild told PopCulture.com ahead of the documentary's premiere he was shocked to learn production had obtained a copy of the tape, during which he interrogates Hansen, as it was part of the state's deal with the killer that it would never be released if he confessed. "I never got a copy of that tape," Rothschild said. "No one ever got a copy of that tape."

Recalling his interrogation of Hansen, Rothschild knew he was dealing with a "monster" as he attempted to get the man to confess his crimes. When confronted with evidence of his murders, "that's when I saw the transformation of Robert Hansen, the mild-mannered Bob the baker, become Robert the serial killer," the former prosecutor recalled of the moment a "look of evil" came over Hansen's face. "Little Bobby Hansen wasn’t winning the game. We had him and he had no leverage."

When Hansen was convicted, Rothschild left his job as a prosecutor to travel with his wife before later becoming a judge. "When you're in the criminal realm, you're seeing the downside of human beings, the horrible things going on in the world, and you don't have contact with good things and good people," he explained of leaving his job. Rereading his opening statement from Hansen's trial for The Mind of a Monster, Rothschild was taken back to that place. "It was so emotional," he said. "It dredged up so much emotion in me to read those words."

After this, Rothschild is ready to move on from Hansen for good, and intends to never speak publicly of the trial again. "He keeps coming back to haunt me. I'm done with that jerk," he told PopCulture. "This is such a grimy, horrific type of a case, and he was such a horrible person. ...I'm Hansen-ed out. I'm not gonna deal with this ever again." The Butcher Baker: The Mind of a Monster premieres on Wednesday, September 2 at 9 p.m. ET on Investigation Discovery.