Exclusive: Fake Firefighter and Fashion Writer — A Case of Jekyll and Hyde

June 27, 2007 — -- On Halloween night 2005, by using a national symbol of trust — the uniform of a New York City firefighter — Peter Braunstein gained access to a former fashion editor's apartment, a woman he barely knew, and terrorized her for 13 hours.

Just last week, Braunstein, 43, once a successful fashion journalist himself, was sentenced to 18 years-to-life in prison after he was found guilty of kidnapping, robbing and sexually molesting the woman.

In his first interview since committing the crime, Braunstein told ABC News correspondent Bill Ritter the details of that night, as well as what turned him into a criminal. "Even the lowest form of criminal generally comes into something with a plan," Braunstein said.

Dressed as a firefighter, Braunstein set fires in the hallway outside the Manhattan apartment of his victim, an ex-colleague at Fairchild Publications, parent of Women's Wear Daily and W magazine. Once inside, he drugged her, tied her to a bed, took off her clothes and videotaped her.

Watch "20/20" Friday at 10 p.m. ET for Bill Ritter's exclusive report.

Ritter met with Braunstein last week in the psychiatric jail at New York's Bellevue Hospital, just after Braunstein was sentenced. He asked him about the disturbing and terrifying incident and how he carried it out.

"You just figured out how to get in?" Ritter asked. "Yeah," Braunstein replied.

"She didn't know that you didn't have a plan? She didn't know you weren't gonna kill her? She didn't know you weren't gonna rape her? She had no idea, and that was torture in and of itself, wasn't it?" Ritter pressed.

"You didn't hurt her physically. You did touch her," Ritter said.

"Yeah, I touched her. ... I think I, like, took, fondled her breast twice."