Sarah Turney36 years old, tried everything to find out what happened to her older half-sister, Alissa Turneydisappeared without a trace at the age of 17 in 2001. Decades after her devastating loss, Sarah began piecing together the painful memories of her childhood in Phoenix and gathering chilling evidence. She now believes her father Michael Turney is solely responsible for Alissa’s death.

“I always thought that growing up, Alissa had behavioral problems and that my father (and Alissa’s stepfather) didn’t like that and was quite controlling,” Sarah told PEOPLE. She claims her father used intimidation, surveillance, and emotional and physical abuse to hurt the person she loved most. “I will never forgive my father. He is one of the worst people ever.”

Michael, however, denied killing Alissa and was acquitted of her murder in July 2023. And he denies ever abusing Alissa during a tense conversation with Sarah on Oxygen. Family secrets: the disappearance of Alissa Turneya docuseries now streaming on Peacock. Despite numerous attempts, PEOPLE has been unable to reach Michael Turney.

“Even to this day, there has never been a single search for Alissa, although the Phoenix Police Department told the media exactly where they wanted to search,” Sarah said. “When asked, I am repeatedly told that the area is too large and too dangerous. At this point, I will settle for just one search. Just one.”

Sarah was 4 years old when Alissa’s mother, Barbara Strahmdied of lung cancer. The half-sisters grew up in a blended family, after Alissa’s mother remarried a year before her death. Eventually, Alissa’s stepfather, Michael, adopted her. Michael’s five other children have all said they think he is responsible for Alissa’s disappearance, and the most vocal of them is Sarah.

At age 12, Sarah never got to say goodbye when Alissa disappeared on the last day of her freshman year at Paradise Valley High School in Phoenix, Arizona. When Sarah returned home later that day, she found her sister’s room destroyed, with a note on his dresser explaining that she had fled to California.

To Sarah, it seemed plausible. Yet Alissa left behind her cell phone, money and makeup – details that would later seem strange to her half-sister and investigators. Their father, Michael, a former sheriff’s deputy and electrician, reported a missing person that evening.

“Alissa was saving her money and planning to move out when she turned 18, so she wouldn’t run away. But a handwriting expert confirmed it was her handwriting,” says Sarah. “I thought Alissa had abandoned me, and I was very, very hurt, so I wasn’t really looking for any other motivation. My dad basically convinced me that she was unhappy and left.”

Soon after, the family moved to another house and Sarah kept all of her sister’s possessions. “I remember being shocked that my father didn’t set up a new room for him in the new house.”

Then, in 2006, the alleged runaway case turned into a possible homicide. A murderer convicted in Florida, Thomas Hymerapparently confessed to killing Alissaaccording to ABC News. Investigators discovered his confession was false, but it led two Phoenix detectives to take a closer look at the teen’s disappearance.

It wasn’t long before they turned their attention to Alissa’s father. Michael maintained his innocence throughout the investigation and continues to do so today. And at first Sarah believed him.

When he was arrested in August 2020Sarah and her then-boyfriend lived with him. “When my boyfriend told me that everyone thought my sister was killed by him, that was obviously a huge deal for me,” she says. “It became very obvious that I was the only person who didn’t believe it, I was in denial. He was my only living relative and my whole life was shattered.”

“As the youngest in the family, taking on all this alone was very difficult,” she continues, holding back tears. “I took a lot of distance from my whole family after this documentary. They think I’m tarnishing my father’s name. They don’t want this to be our legacy.”

She would like to have the answers to why her brothers don’t want to continue helping with Alissa’s case. “It’s still hard to deal with,” she said softly. “But I can tell you they all believe (Michael) did this and he believed it before me. I think one of the biggest misconceptions is that I’m out here trying to convince my family when I was the last to do it I think this happened. It breaks my heart, and even more so for Alissa. She loved me and her brothers fiercely. she would be heartbroken to see how things turned out unfolded.

One night, while Sarah was digging through home videos, she found footage of her sister calling their father a “pervert” in 1997. “I was panicked. I was terrified when I first saw it,” Sarah says. “I was like, ‘Oh my God.’ My first thought is how could the police have missed this? And then my second thought was: I need to share this with people.”

Sarah says she defended her father for so long because she believed him, even when he was behind bars. She says she had to take care of all his property and responsibilities at home and helped him file more than 90 petitions in court. “I don’t miss any relationship with him because it was just abuse,” she says now of her sister.

She claims Alissa first reported to a school teacher when she was eight years old that she was having sex with their father. “That led me to believe that this had been happening for a very long time.”

Alissa’s third-grade teacher told authorities that the teen once confided in him that she was having sex with her father, according to NBC News. The teacher did not report the allegation to authorities because she said Alissa immediately denied it. “But the teacher confronted Mike and he denied it, saying, ‘Alissa thought sex was when people kissed each other goodnight,'” said William Andersen, the detective. Phoenix police, to the media.

“Our mother took us both to a doctor to check for physical and sexual abuse before she passed away in 1993,” says Sarah. “She would definitely have had suspicions if she took us to the doctor for a sexual assault check-up. I just would have liked to know the results of the test. But I had been informed of the sexual assault by the police when her friends Many people have also contacted Alissa to tell them about the horrific abuse.

The first time Sarah confronted her father was around 2014-2015, while he was incarcerated. “I called him one day and said, ‘Dad, none of this matters. Why didn’t you tell me all this?’ He really blew me away and changed the subject, but once I saw all the evidence, it became pretty clear.”

Two months after Michael’s release from prison, the two spoke again in October 2017 at Starbucks, which is featured in Family secrets. Sarah interpreted a comment he made – daring her to come to his deathbed to get truthful answers to all the questions she asked – as a confession. But, as one detective said in the documentary, there was no physical evidence or crime scene, and police couldn’t use “conversation snippets” to make their point.

“It was scary,” Sarah says of coming face to face with her father. “I didn’t want to be there. I think it’s still scary to talk to my dad, but I just wanted answers and I went there looking for an honest conversation. I knew he wasn’t going to not be nice, and I knew he wasn’t going to tell me the truth, but it was the first time I’d been able to talk to him in so many years outside of a taped prison line or without him a detention officer is watching him, and I was hoping he would a mistake.” And he certainly did so with many of his statements. It was horrible and so shocking. ”

She continues: “It erased the 0.01% doubt I had in my mind that he could have been innocent. It sealed everything for me. I know they don’t talk about it in the documentary, but that’s in addition to him following up shortly after saying, “I will confess if they give me a lethal injection within 10 days of this confession,” which they do. she published on the podcast that she created in 2019, “Voices for Justice”.

The last time Sarah spoke to her father was in February 2024 for the documentary Oxygen. “I don’t think his words really hurt me anymore. He was cruel my whole life,” she says, thinking back to the moment she left her father after he told him to. stop talking to him about his sister’s death.

“I just didn’t realize it when I was younger. Now when he’s so outwardly fake like that, it’s irritating and feels like a waste of time. Let’s get to the point and stop pretend we’re here to have some semblance of a daughter-father relationship,” she said. “It’s so telling. I think when you listen to this conversation, it’s so clear. He’s so mean, and the statements he says are so telling about what he did.”

Today, Sarah cherishes Alissa’s happy memories and has kept all of her belongings. She still has her ball gown, her writings and drawings, her jewelry, her furniture, her blankets and her photos to remember her. “We used all of his real elements in the documentary,” she adds. “The blanket at the foot of his bed in one scene came from our mother; she knitted it. So yes, I kept everything.”

But Sarah insists she has to relive the pain and that talking about what happened to her sister is traumatic for her. “I never wanted to get into this fight. It’s not my first choice, but it’s what I have to do for Alissa and what the police told me to do. I’m willing to suffer and working through this trauma because it helps Alissa…at the end of the day, it’s not about me,” she says.

“I lost my personal relationships because of this. I destroyed my employability – and it’s all for her. Unfortunately, there is no real crime entertainment without trauma. It is extremely difficult and painful, and I really gave up my whole life for her. I will never give up.”

It is also his only option to seek the truth about his sister. “I believe my father was (allegedly) a serial rapist-murderer and a pedophile domestic terrorist. I hope he admits it, but he’s just too selfish. I think he gives way more “I care less about protecting one’s ego than protecting one’s children.”

She pauses, choking. “I’m going to cry, I still want to tell Alissa I’m sorry. I wish I could have been a better sister, seen what was happening in our house and that I love her.”