For years, US woman Sarah Turney had suspected her father was involved in the disappearance of her missing sister Alissa.
While Michael Turney has always denied any involvement in Alissa Turney's disappearance, Sarah has spent years campaigning for police to take action.
After exhausting every avenue, from podcasts to her own investigations, Sarah turned to TikTok, where she shared videos in her bid to get "justice for Alissa".
After being viewed by millions of people around the world, the clips gained a renewed interest in the cold case, and Michael Turney was recently charged with second degree murder.
It's a story that sounds like a movie straight out of Hollywood, but tragically it's a real life case.
Seventeen-year-old Alissa vanished in 2000 from the family home in Phoenix, Arizona, where she lived with her stepfather Michael and her five other siblings.
Sarah said Alissa had been like a mother to her after their mum Barbara Strahm died of cancer when they were young, leaving them in the sole care of her father.
The sisters didn't share the same biological father, but they were incredibly close – Alissa even called Michael "dad".
Police initially believed Alissa was a runaway, but as Sarah got older she realised several things didn't add up.
Her father had pulled the missing teen out of school early the day she disappeared, Buzzfeed News reported.
Police then found a note from Alissa written on the day of her disappearance saying she had run off to California.
They also later found bizarre contracts signed by the teen saying she had never been abused by Michael.
Authorities also found surveillance equipment inside the family's house, which her stepfather admitted to setting up. He claimed he was monitoring his children for safety reasons, ABC News reported.
Police also found all inbound and outbound calls were recorded.
In 2009, Michael Turney told ABC News he returned home the day Alissa vanished and discovered the note. He denied he was involved in her disappearance.
As a child, Sarah Turney didn't suspect her father, but that changed over the years.
In 2017, she began campaigning in the media for her father to be charged, starting Instagram and Facebook accounts, followed by a podcast - Voices For Justice - in 2019.
Despite public interest the case seemed stalled, with US police not taking any action against Michael Turney.
That was until Sarah created a TikTok account in April, where interest in what happened to Alissa exploded.
She shared chilling surveillance footage allegedly taken by Michael of Alissa at work – one clip where the teen seems to be warning a young Sarah about alleged abuse got tens of millions of views.
Sarah told Elle.com she started the TikTok account to reach a new, younger audience and included "as little of my own speculation as possible and just present the facts".
One of Sarah's most-watched videos is a recorded conversation she says she had with her father following his release from jail in 2017 where he spent time for an unrelated offence, the unlawful possession of unregistered destructive devices, following a raid on his house in 2010 that uncovered 26 pipe bombs.
In the video, Sarah asks her dad if he is responsible for Alissa's disappearance, to which he replies: "Be there at the deathbed Sarah, and I'll give you all the honest answers you want to hear."
In August 2020, just four months after Sarah started her TikTok account, a grand jury charged Michael with second degree murder over Alissa's disappearance.
Sarah tweeted at the time that she was "shaking and I'm crying" over the news, telling people to "never give up hope that you can get justice".
"I felt a lot of different emotions [afterwards]," Sarah told Elle.com.
"I was sad that he still refused to give me any answers … I was hopeful that [putting those statements on TikTok] would prompt the police to finally bring him to a grand jury for questioning."
In a press conference after Michael Turney's arrest, Maricopa County Attorney Allister Adel praised Sarah for showing "perseverance and commitment" that is "a testament to the love of a sister".
"This passion you have you have demonstrated to her during your journey is something that will keep Alissa's memory alive forever," she said.
Michael Turney is now 72. Alissa Turney's body has still never been found.
Now Sarah is turning her attention to other missing persons cases across the United States, and is hoping her TikTok presence and determination can help other families in a similar position to her.