How a Nine-Year-Old Girl's Memory Cracked the Elizabeth Smart Kidnapping Case

Updated 15:18 25 Sep 2026 GMT+1Published 15:24 21 Jan 2026 GMT

Elizabeth Smart's kidnapping became national news in the US when she went missing for over nine months

The Guinness Book of World Records is useful for teaching kids all sorts of facts but it also once helped identify a kidnapper.

Mary Katherine Smart had been in the room when her sister Elizabeth was taken back in 2002, with her case quickly becoming national news in the US amid a huge search for the teenager.

Police had believed that a man who died in custody was responsible for the kidnapping, but it wasn't until four months after her disappearance that their minds were changed by none other than Mary, who was just nine at the time.

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She had pretended to be asleep out of fear as her older sister was taken away with a knife at her throat and it turned out that a copy of the Guinness Book of World Records would help to identify who was responsible.

Speaking in Netflix’s Kidnapped, which released back in January, she revealed how reading through a Guinness World Records allowed her to figure out who it had been.

After Elizabeth was taken, much of the focus of the investigation was on her nine-year-old sister, particularly because she said she thought she recognised the voice of the kidnapper.

Speaking in the Netflix documentary, Mary Katherine explained how she was able to eventually help find the man who kidnapped her sister, Brian David Mitchell.

She said in the new film: “After my sister was kidnapped I was very frightened to go to sleep, my dad would have to come in and tuck me in and while I was waiting for him I would be looking at books or racking my brain about who could have taken Elizabeth.

“One particular night, four months after Elizabeth had been taken, I was flipping through the Guinness World Records.

“For some random reason in that moment the name popped into my head and I knew immediately who was in my bedroom June 2002, that’s the man who kidnapped Elizabeth.”

Her dad Ed Smart said: “Lois and I had gone out for the evening and when we got home Mary Katherine had said ‘I think I know who it is, and she said it was ‘Immanuel’.”

Immanuel was the preacher’s name Brian sometimes went by and had met their mother Lois whilst preaching in town as a homeless man.

Mary Katherine figured out who had taken her sister by reading the book (Netflix)

She gave him Ed’s business card and suggested he could help work on the house, an offer he took them up on.

Mary Katherine had been reading the Guinness World Record book when he had done work on the house and so returning to reread it had jogged her memory of him.

Whilst police were initially sceptical, believing that a prior suspect who had died in custody was behind the kidnapping, it turned out she was right and ‘Immanuel’, aka Brian David Mitchell, was the man responsible.

The family eventually released a sketch of Brian, leading him to be spotted and arrested by police.

Elizabeth Smart was 14-years-old when she was kidnapped from her home in Salt Lake City (Netflix)

Elizabeth was held in captivity for nine months in which time she was raped, forced to drink alcohol until she threw up, and was ‘married’ to him in a bizarre ceremony.

24 years on from her abduction she speaks bravely in the documentary about her harrowing experience, telling Netflix’s Tudum that in earlier versions of the doc she could tell the filmmakers didn’t want to re-traumatise her.

She said: “They wanted to be so sensitive to me. Well, I didn’t go on vacation, I definitely wasn’t just sunbathing up in the mountains waiting for someone to come and rescue me.

“When I saw the final cut [which includes her discussing the details in graphic accuracy], I was like, ‘Thank you’, [The filmmakers] made me proud. They did justice to my story.”

Kidnapped: Elizabeth Smart is available to stream on Netflix now.

Featured Image Credit: Netflix

Topics: TV and Film, Film, Documentaries, True Crime, US News