When Sherri Papini went missing while out for a jog in November 2016, her fellow residents of Redding, Calif., couldn't help but compare the circumstances to another shocking disappearance in their community 18 years beforehand.

"While searching for Sherri, all I could think about was Tera Smith," her sister Sheila Koester recalled in the recent Hulu docuseries Perfect Wife: The Mysterious Disappearance of Sherri Papini, "and how she had left and never came back."

Sherri and Tera, both pretty blondes, attended the same high school in the 1990s. They each vanished near the Old Oregon Trail, not far from either of their homes. 

But as the world eventually found out, Sherri faked her abduction and spent three weeks with an old boyfriend before reemerging on Thanksgiving. She eventually spent 11 months in prison after pleading guilty to a count apiece of making false statements to a federal officer and mail fraud. She remains on supervised release until 2026.

Tera told her younger sister Sierra Smith that she was going out for a jog on the night of Aug. 22, 1998, and would be back in 20 minutes. The 16-year-old never made it home.

"Twenty-five years is a long time to be without our daughter," mom Marilyn Smith told KRCR in 2023 ahead of the anniversary of Tera's disappearance. "And, to think of what might [have been] with our family... We're really grateful for the community and their support. People still approach us and say they remember Tera and we're grateful for that."

She and Tera's father Terry Smith admittedly gave up hope a long time ago that Tera would come back safely, but they still want justice.

Here are all the details on the haunting cold case brought back into the news by Sherri's kidnapping hoax:

Who is Tera Smith?

Tera Lynn Smith, the oldest of four siblings, "had a lot of passions and interests," mom Marilyn told NBC News' Dateline in 2022. "She loved horses. She loved basketball, nature. Her freshman year of high school, she was homecoming queen and arm wrestling champ."

The Central Valley High School junior was also a talented writer who loved poetry and had "a deep spiritual side," Marilyn continued. Added father Terry Smith, "We have volumes and volumes of her journals."

She started doing Taekwondo "because of the connection to the earth," Terry shared. "All that really appealed to her."

Tera also helped out at the family business, the Oasis Fun Center, a spot for miniature golf and other games in nearby Shasta Lake.

What happened to Tera Smith?

On the Saturday night in August 1998 she went missing, Tera was grounded and not supposed to go out before she was due to work that evening at the Oasis.

"I think she had snuck out," Marilyn said, explaining the punishment. "She wasn't the perfect child, by any means."

She and Tera had spent much of the day together running errands before Marilyn dropped her eldest child at home and went ahead to work. When Tera didn't show up as expected an hour later, Marilyn called the house.

Daughter Sierra told her that Tera had said she was going for a 20-minute jog but hadn't returned, Marilyn recalled. "I came home and just drove all the roads that I thought she might be jogging on," she said, "and couldn't find her." 

Sierra, who was 11 at the time, remembered how their parents used to tell them never to leave the house at night on their own. "I was like, 'Tera, you're not allowed to go,'" she told KRCR in 2022. "She told me that she would be back before our parents ever got back home. I remember watching her as she jogged out of my line of sight."

Tera's next-youngest sister Kyra Smith was at a friend's birthday party when she got a call from her parents to fill in for Tera at work—and she wasn't happy about it. 

"So I was frustrated with her until...it turned real," Kyra told Dateline. "Until we realized she might not be coming home."

Who was Tera Smith dating when she disappeared?

Before they called police, Tera's family called a bunch of her friends, one of whom said the teen may have been having some sort of relationship with her married Taekwondo instructor, 29-year-old Troy Zink.

When Terry talked to Troy that night, the martial arts instructor said he'd seen Tera earlier that night when he gave her a ride, Terry told Dateline.

The Shasta County Sheriff's Office said that Troy, while he was interviewed during the course of the investigation, was never a suspect or person of interest in Tera's disappearance.

"Gave us the same story that he stuck to throughout," Terry said. "That he had picked up Tera, dropped her off about a mile and a half from our house—two miles, three miles from our house. And then had gone up to… a hill nearby called Hang Glider Hill."

Days later, Terry recalled, they were going through Tera's bedroom looking for clues when they found what appeared to be a letter to Troy about ending whatever was going on between them.

Troy—who, per court records reviewed by Dateline, was convicted of spousal rape in 1992 (a charge he denied)—told police that Tera called and asked to see him on the night in question. When he showed up at the Smith family home, she asked if he could loan her $2,000, Troy said, according to court documents obtained by Dateline.

He told Tera he didn't have that much on him but he'd give it to her if she told him what it was for, Troy told investigators. She got angry, Troy continued, and then asked for a ride.

Troy told authorities he dropped her off by Old Oregon Trail and she headed off jogging.

During a related search of his Taekwondo studio, however, officers found firearms—which he was not supposed to have as a convicted felon.

He maintained the guns belonged to his father, but Troy was found guilty of possession of a firearm by a felon on June 24, 1999, and was sentenced to four years in prison, per NBC News. He appealed in 2001, arguing that it was impossible for him to get a fair trial in the wake of all the coverage of Tera's disappearance, but it was denied.

Were there any suspects in the disappearance of Tera Smith?

To date, no arrests have been made or suspects named in connection with Tera's disappearance.

Investigators "did the due diligence," Shasta County Sheriff's Lt. Chris Edwards told Dateline, "and, you know, investigated and interviewed people that were close to her, that knew her, and followed all those leads out."

Was Tera Smith ever found?

No trace of Tera has ever been found, nor evidence to point to what may have happened to her.

Per the California Department of Justice's missing person site, the 5-foot-7 blonde with blue eyes was last seen wearing a white sports bra, multicolored running shorts, and white and navy Nike running shoes.

"At the time, we really felt satisfied that they were giving it their all," Terry told Dateline of authorities' efforts to find Tera. "They brought in cadaver dogs....We have a lake nearby…They nearly drained that lake."

He continued, "We feel like they really gave it their all for probably six months to a year. And then it was an important case for another year or two. And since then, it's shelved. It's completely cold. Stone-cold."

While Tera's mom called the realization that she wasn't coming home "a gradual process," Terry said he felt like the search was a lost cause after two days.

"I think Marilyn held on to hope far longer than I did," he said. "I was convinced that she was gone from almost the get-go."

How did Sherri Papini's kidnapping hoax affect Tera Smith's family?

At the time of Sherri's disappearance in 2016, Shasta County Sheriff Tom Bosenko still kept a picture of Tera on his desk.

Sherri "is 34 years old, but she looks much younger," he told the Sacramento Bee while the search was underway. "They could probably pass for sisters."

Sherri's then-husband Keith Papini reached out to Tera's father for advice during that time, Terry telling the Bee he could only advise the scared spouse to insist that investigators do everything possible to find his wife.

"I didn't have a lot of comfort to offer him," Terry said. "I'm not real confident that anything's going to come out of it, but how do you tell somebody five days after their wife's gone missing that she's probably gone for good?"

But Sherri came back on Nov. 24, 2016. And more than five years later, she was arrested for lying to federal authorities about being kidnapped. 

"I would love to say that it's not upsetting and just to be able to have so much compassion," Tera's sister Sierra told KRCR in March 2022 after Sherri's arrest, "but I can't because it is so upsetting."

Sherri even had dinner at Marilyn and Terry's house at one point after her return.

"She has to be sick to have come up with that story and to hurt herself the way she did," Sierra said. "She's just not well."

In Hulu's Perfect Wife, Keith lamented going to see Tera's family under what he didn't know at the time were false pretenses.

Sherri "allowed me to take her over to that house after the fact," he said, "and she just lying straight to their face is something that has been very difficult for me [to process]."

Where does the investigation into Tera Smith's disappearance stand?

Tera's disappearace is still an open missing person case, Shasta County Sheriff's Sgt. Jake Duncan confirmed to E! News.

He said they continue to work on any new leads and information that comes in and the public is encouraged to call in with tips.

Lt. Chris Edwards told KRCR in August 2023 that hope remains alive in their office.

"I do feel that somebody out there does have information on this case," he said, "and we can get that solved."

In lieu of hoping to see their daughter again, the Smiths would at the very least like some answers.

"There are plenty of cold cases out there that may never be solved," Terry told Dateline. "We just hang on to the hope that ours won't be one of those."

Kyra added, "We want justice still. We don't want someone capable of doing something like this out just living their lives."

Where is Tera Smith's family now?

The Oasis Fun Center is still in the family, run by Marilyn and Terry's son, Trevor Smith. He and sisters Kyra and Sierra are all married with kids of their own.

On the 25th anniversary of Tera's disappearance in 2023, her family picked up trash on Old Oregon Trail, where she was last seen, as they did every year. "Tera was an adamant recycler," Terry told KRCR, "and she loved keeping the earth clean."

Kyra moved away from Redding as an adult, but resolved to focus on Tera's life "and all the good," she told Dateline. "Because I don't want to focus on the ugly details of her disappearance."

Sierra also wants to remember Tera as she was "instead of finding something I wouldn't want to see or know."

She told KRCR in March 2022, "I think we all feel pretty at peace with the fact that she's gone and we'll see her in the next life."