Dangerous Games
In 2012, Lizzi Marriott was a 19-year-old New Hampshire student when she disappeared after visiting her co-worker, Kat McDonough, and Kat's boyfriend, Seth Mazzaglia, in their apartment. Kat initially claimed Lizzi's death was accidental, but later testified that Seth strangled Lizzi with a rope after she rejected his sexual advances. "48 Hours" correspondent Troy Roberts reports. This classic "48 Hours" episode last aired on 9/19/2015. Watch all-new episodes of “48 Hours” on Saturdays and stream on demand on Paramount+.
- Duration
- 39m
- Broadcast on
- 22 Oct 2026
- Audio Format
- other
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[MUSIC PLAYING] It was inevitable that Seth Mazzelia was going to kill. And Lizzie Marion was the perfect victim for him. He attacked, he raped, and he murdered. This is his victim, 19-year-old Elizabeth Marion. [MUSIC PLAYING] Lizzie was always happy, and she always found the best in everyone. She has such an aura about her. You know, people wanted to talk to her. Maybe he didn't. I thought her in the state calls Catherine McDonough. It was clear that this trial is going to all of be about Kat McDonough's testimony. Ms. McDonough, how do you know what Seth Mazzelia did to Elizabeth Marion? I was there. Kat was always into strange things. She was always talking about her different personalities. She was dating an older guy, Seth Mazzelia. The relationship between Seth and Kat was going to be a dangerous problem. Seth was into the BDSM type thing. Did he engage in bondage, domination, master submissive? Yes. This case is not a romanticized, fictionalized novel. Of you may have read. This was the exercise of power and control. Lizzie was attractive. She was what he had been looking for. The defendant in McDonough schemed about how they could exploit her sexually. Was that why you reached out to Lizzie Mariont invited her to the apartment? Yes. Seth was hoping there'd be some sort of sexual encounter. And it all seemed to be going according to the defendant's sexual plot, until Lizzie said no. He didn't like to be told, though. And what the master wanted, he got. The defendant put on gloves, and he grabbed a rope. Ms. McDonough, who killed Elizabeth Mariont? Seth Mazzelia. But during the trial, I was surprised how many people thought she was lying. Ladies and gentlemen, Seth Mazzelia did not cause Ms. Mariont's dad. Pat McDonough is lying. The physical evidence shows what? Sex. But there was sex.
Transcription truncated.
In 2012, Lizzi Marriott was a 19-year-old New Hampshire student when she disappeared after visiting her co-worker, Kat McDonough, and Kat's boyfriend, Seth Mazzaglia, in their apartment. Kat initially claimed Lizzi's death was accidental, but later testified that Seth strangled Lizzi with a rope after she rejected his sexual advances. "48 Hours" correspondent Troy Roberts reports. This classic "48 Hours" episode last aired on 9/19/2015. Watch all-new episodes of “48 Hours” on Saturdays and stream on demand on Paramount+.