Scott Sherman is the mayor of Winona, Minnesota, a small city on the banks of the Mississippi. "There's just something about Winona that keeps pulling you back," he told "48 Hours" correspondent Peter Van Sant. "Living here in Winona is really cool."

It's so cool that TV and film star Winona Ryder is named for the town, as she told the world in a 2020 Super Bowl ad:  "There's something about this place, something that feels so me …"

Madeline Kingsbury, 26, also felt that certain "something" about Winona. So, when Mayor Sherman heard that she had gone missing, he wanted to help.

"I felt that Maddi was a daughter of Winona," said Mayor Sherman. "She was a bright young woman working through school, working … a — a job in Rochester and raising kids all at the same time, that's a lot. … So, I had respect for Maddi.

And Sherman thought he could help because, as an avid bicyclist, he rides the woodsy paths around Winona all year long.

"You know the back roads of this area?" Van Sant asked. "I do," said Sherman.

"And you went out yourself," said Van Sant. "I did," Sherman replied.

But as mayor, Sherman felt his first job was to support Maddi's distraught mother Krista Naber when she arrived at the search command center.

"She gave me a hug that I will never forget the rest of my life," Sherman said. "It was a hug that showed fear, concern."

"And so what were — what message were you sending with that hug?" Van Sant asked.

"I'm here for you. We will do our damndest to find her," said Sherman.

WHERE'S MADDI KINGSBURY?

Maddi's family first began worrying about her late in the afternoon of Friday, March 31, 2023, when Naber realized she had not heard from her daughter for nearly the entire day.

Krista Naber: Something in my gut just didn't feel right.

Peter Van Sant: Mother's intuition?

Krista Naber: Right.

Naber contacted Megan, Maddi's older sister, but Megan said she was not overly concerned.

Megan Kingsbury: I sent her a couple of text messages anyway … "Hey mom, hasn't heard from you. Can you call her? Can you text her back? … She's concerned." … and she didn't reply to that.

At the time, Maddi was living with Adam Fravel, the father of their children. The two had met in college at Winona State University.

Megan Kingsbury: He was outgoing, and seemed interested in getting to know us, and he seemed very, almost infatuated, I guess, with … Madeline.

While still in college, Maddi and Adam learned they were expecting their first child and decided to settle in Winona.

Theresa Sis Mejia: He manned up, he manned up.

Theresa Sis Mejia, Fravel's sister, says Adam quit school to support his new family.

Theresa Sis Mejia: He knew he was gonna be a dad. He went and got a job … and he had that job up until COVID, and then he got laid off … while he let Maddi continue college so that she could graduate … and she did. She graduated and he supported her.

After graduation, Maddi began working at the Mayo Clinic and became a clinical research coordinator. And Maddi's father David Kingsbury said she recently had begun studying for an advanced degree.

David Kingsbury: She was … a graduate student in a master's program at the University of Minnesota … Had just completed her first semester there and was doing very well.

Fravel, who had studied computer science in college, began taking flying lessons with an eye toward getting his pilot's license.

Theresa Sis Mejia: When he was taking pilot lessons like that, he felt so accomplished … It made him feel good. And I was so proud of him for doing it, for doing something for himself.

Krista Naber: I enjoyed being around him … I could tell that he really cared for Madeline.

On the evening of March 31, Megan Kingsbury was hours away from Winona when she reached out to Fravel, who said he was concerned.

Megan Kingsbury:  He said … I got home today and she was gone …

Fravel and the children were at his parents' home in Mabel, an hour south of Winona. That's when Megan Kingsbury messaged Maddi's close friend Katie Kolka, who lived in Winona: "My parents and I haven't been able to get in contact with Maddi all day ..." Katie responds: "I'm on my way over there right now."

The house was eerily silent, and it was at that point Kolka called the Winona police.

Peter Van Sant: And you want this missing persons report to be filed, but what did they tell you?

Katie Kolka: They told me that I wasn't able to report it because it hadn't been 24 hours yet.

Megan Kingsbury: I was pacing in my kitchen. I was getting really really worried.

So was Maddi's father who tried to reach her.

David Kingsbury: Where are you? What's going on?

The next morning, with Maddi now missing nearly 24 hours, the Kingsbury family filed a missing persons report.

And then Fravel went to Facebook asking for help. His post read in part: "If anybody has seen Maddi … please contact the Winona PD, me or any of her family members … Please help me find the mom to our 2 beautiful kids."

Mary Fulginiti | "48 Hours" consultant: The police went to great lengths, I have to say, to try to … find Maddi quickly … because they know that there's a ticking clock on these things.

And the investigation took off.

Mary Fulginiti: It's extraordinary what they did.

"TIKTOK, I NEED YOU TO DO YOUR THING …"

The news that Maddi was missing spread quickly through Winona and beyond. Hailey Scott, one of Maddi's sorority sisters, wanted to help.

Hailey Scott: I reached out to our sorority … I reached out to news outlets … I was grasping at straws.

At the same time, detectives reached out to Adam Fravel. According to police reports, Fravel told them how on the morning of March 31, the couple dropped off their children at the daycare center.

Investigators confirmed the drop-off after speaking to the daycare provider who gave police security video.

This video has never been seen by the public until now. It was one of the last times Maddi is seen on video before she vanished. Police say Fravel told them he and Maddi returned home after the drop-off and she went to her office in the basement to do a little work before heading to the Mayo Clinic.

Mary Fulginiti: I have taken a look at all the evidence that we have thus far in the Maddi Kingsbury case.

Mary Fulginiti, a former prosecutor and defense attorney, is a "48 Hours" consultant. She says that in his police interview, Fravel told detectives he left Maddi his car and borrowed her blue minivan to haul some boxes.

Mary Fulginiti: He … proceeded to put some boxes in the van that he was going to move to his parents' house … He said he didn't see Maddi again … He drove to his parents' house on Highway 43.

Police say Fravel told them he got as far as the township of Choice, Minnesota, when he realized he had made a mistake.

Mary Fulginiti: The boxes that he had in the van were ones that he actually wanted to put in storage. So he turned around and he went back to the home.

Police say Fravel told investigators he arrived back at his Winona home around 11:30 a.m. and saw his car still in the driveway.

Mary Fulginiti: He said he had texted her a few times, asking about dinner and whether or not she was gonna pick up the kids … There was no response.

Police say Fravel told them he'd assumed Maddi had carpooled to work and when he did not hear from her, he went alone to do that pick up of the kids. Again, the video from the daycare appears to corroborate that part of Fravel's story. 

Mary Fulginiti: So he ultimately picked up the children around 4:20 or 4:30, um, from daycare and brought them to his parents' house in Mabel, Minnesota.

During a police interview, investigators noted that Fravel had "fresh scratches" on his face the day after Maddi disappeared. Fravel's sister says he told her the scratches came from a friend's dog.

On Saturday, April 1, police searched the Winona house where Fravel lived with Maddi. Investigators reported they saw no overt signs of foul play.

Mary Fulginiti: But what was in the house was her purse, her jacket, her credit cards, um, but no Maddi.

Two days later, an anxious Megan Kingsbury rushed out of her shower and alerted her TikTok followers to what was going on.

MEGAN KINGSBURY TIKTOK POST:  TikTok. I need you to do your thing. I need your help. This is my sister Madeline Kingsbury. Um, she's missing … 

Megan Kingsbury: I wasn't thinking about the fact that I was in a towel. 

The post eventually had over a half million views.

MEGAN KINGSBURY TIKTOK POST: … Help us find her. She's got two kids. She's my best friend, she's my little sister. We need to get her back. Please help us. 

Peter Van Sant: You're obviously in terror here … The look on your face. But you're reaching out for help and people wanted to help.

Megan Kingsbury: Yes.

CBS MINNESOTA | NEWS REPORT: So many people have asked to help look for Madeline Kingsbury that it allowed law enforcement to expand their search …

Hailey Scott: There's no guidebook on how to search for a missing loved one … and searching for her was easily one of the most traumatic things I've ever experienced in my life.

By the end of the weekend, there was no sign of Maddi. Day by day, Megan Kingsbury continued to post updates to TikTok.

MEGAN KINGSBURY TIKTOK POST: It's Tuesday the 25th ... still no Madeline … now next week is May. We're still in this hell …

Megan Kingsbury: I feel like all of us, like every night, we would look out — it's cold. It's dark. Is she like laying out there somewhere? … Is she like trapped somewhere? … and you just — you don't know what to do.

Behind the scenes though, investigators began taking a harder look at Fravel, especially after Maddi's friends came forward with some disturbing stories.

Hailey Scott: Madeline called me shortly after an incident happened between her and Adam … where he had told her that if she wasn't careful, she was going to end up just like Gabby Petito.

The Gabby Petito case fixated the nation in the fall of 2021, after the young woman from Long Island was found dead one month after she seemingly vanished from the face of the earth.

Hailey Scott: I told her you need to get out and you need to get it … get out now. That's not an empty threat.

A FATHER'S WARNING: "HE IS GOING TO KILL YOU"

Years before Maddi vanished, her sister Megan Kingsbury says the on-again, off-again relationship between Maddi and Fravel seemed to be headed for a bad ending.

Megan Kingsbury: He just wasn't nice to her … He didn't act like he loved her. He didn't help take care of the kids. He didn't clean.

Peter Van Sant: And honestly, did you reach a point where you — you advised your sister, you know, perhaps it's time to move on in your life from him?

Megan Kingsbury: Many times.

Maddi's father David said it pained him to see how shabbily Fravel treated Maddi.

David Kingsbury: I think she literally poured out a river of love for him and she got nary a drop in return.

Maddi's stepmother Cathy Kingsbury says Maddi often called, saying Fravel was of no help with the children.

Cathy Kingsbury: She'd be just sobbing miserably that Adam's not helping. I hate this.

But Maddi's family and friends say there was more than just tearful arguments. About three years before Maddi went missing, Hailey Scott says she witnessed Fravel slap Maddi during a video call. Scott and Maddi were talking, Scott says, when Fravel appeared in the background and began shouting at Maddi.

Hailey Scott: He yelled, "I don't understand why this house is such a f