Where Is Elizabeth Smart’s Sister Mary Katherine Now? How She Helped to Solve the Kidnapping Case

Netflix’s Kidnapped: Elizabeth Smart has had viewers gripped as it details one of the most high-profile missing-person cases in modern history: the 2002 abduction of 14-year-old Elizabeth Smart from her family home in Salt Lake City, Utah. The documentary revisits the nine-month search, the public sightings that ultimately led to Elizabeth’s rescue, and the legal aftermath for her captors, Brian David Mitchell and Wanda Barzee.

But the series also re-centers someone who was there from the very beginning—and whose memory became one of the most pivotal breaks in the case: Elizabeth’s younger sister, Mary Katherine Smart.

She was just nine years old at the time of the kidnapping and was in her shared bedroom with Elizabeth when Mitchell broke in and kidnapped her.

In later retellings, Elizabeth has been clear about the impact her sister had on her case (and life), telling Netflix, “She saved me.”

So, who is Mary Katherine Smart, how did she help investigators, and where is she now?

Mary Katherine Smart is Elizabeth Smart’s younger sister. In the years since Elizabeth’s rescue, Mary Katherine has largely lived outside the spotlight, but her role in the case has remained central—she was the child who heard a kidnapper’s voice in the bedroom she shared with her sister, which later helped identify the man responsible.

In Kidnapped: Elizabeth Smart, Mary Katherine appears as part of the family’s retelling, reflecting on what it meant to be a child witness to a crime that would dominate headlines across the country.

While Elizabeth went on to become a prominent advocate and founder of the Elizabeth Smart Foundation, Mary Katherine has kept her life more private.

On the night Elizabeth was taken, the intruder entered the bedroom the sisters shared. Mary Katherine, just nine at the time, later described staying still and pretending to be asleep, listening to the man speak.

In the documentary, she says, “I was nine years old when Elizabeth was taken. I missed not having my sister. She was my best friend.”

As the investigation unfolded, authorities initially pursued other leads. But months later, Mary Katherine reportedly had a breakthrough and recognized the voice as belonging to a man the family knew as “Immanuel,” a street handyman who had previously done work at the Smart family home and who therefore knew the sisters and the home’s layout.

After Mary Katherine’s breakthrough, investigators honed in on Brian David Mitchell, who used the religious name “Immanuel” and who presented himself as a self-styled prophet. The identification helped move the case away from dead ends and toward a suspect who, crucially, would later be recognized in public after Mitchell’s family provided photographs of him and a police sketch was widely circulated.

Speaking about the vital role her sister played in her rescue, Elizabeth told TODAY, “Had she not remembered who had kidnapped me, who’s to say that I would be here today?”

Today, Mary Katherine Smart is reported to be living a much quieter life than many people might expect, given her connection to such a widely known case.

Recent reporting connected to the Netflix documentary describes her as working in education, having also earned a master’s degree in applied behavior analysis. “I love working with kids. I love behavior,” she said during a 2023 news appearance.