The man who escaped "The Dexter Killer"

Mark Twitchell was reportedly fascinated with the Showtime series "Dexter" and aspired to be a serial killer. Twitchell is now behind bars for murdering a man, but authorities believe he intended to kill others. 

Gilles Tetreault was excited for a date with a woman he met online.

"She — she was very attractive looking," Tetreault told "48 Hours" contributor Troy Roberts of the woman named "Sheena."

She sent directions that took Tetreault to a garage, but as soon as Gilles walked in, he was attacked by a man.

"He's about 6 foot and has a black and gold hockey mask all painted up on his face," Tetreault explained. "There's this chill down my back, as I — wow, this is no date."

The masked man ordered him to the ground at gunpoint.

"And he tore a piece of tape, and he covered my eyes with it," Tetreault recalled. "And I start hearing different things ... my head is just racing, like it's like thinking, 'What's goin' on?  What's he gonna do? Is he takin' another weapon out?'"

Tetreault decided he wasn't waiting to find out. "I can't do this, I gotta fight back … so I got up and I ripped the tape off my eyes," he said.

After a violent struggle, Tetreault broke free and escaped. Embarrassed, and believing he had been a victim of a botched robbery, he didn't call police.

Little did he know that a week later another man, Johnny Altinger, would be lured to that same garage and lose his life. 

Twitchell will be up for early parole next year. "48 Hours" takes a look at his obsession with the character of Dexter Morgan and the revealing letters Twitchell sent from prison in "The Dexter Killer."      

"Dexter" airs on Showtime, which, like CBS, is a division of Paramount Global.