What Happened to Sherri Papini’s Schoolmate Who Also Vanished 18 Years Ago in the Same City?

On Aug. 22, 1998, Tera Smith, then 16 and the high school homecoming queen of the freshman class, left home in Redding, California, dressed to go jogging.

She was never seen again.

Sherri Papini — a mom of two and former schoolmate of Tera’s who disappeared 18 years later during a jog in Redding about two-and-a-half miles from where Tera vanished — had a luckier outcome: She was found alive, but beaten and chained, on Thanksgiving morning, following an apparent abduction.

Papini’s case continues to baffle investigators — and it bears some seemingly baffling similarities to Smith’s case, though Shasta County Sheriff Tom Bosenko tells PEOPLE investigators “have not developed any evidence the two cases are linked.”

Still, several days after Papini disappeared, her husband, Keith Papini, reached out to Smith’s father for advice.

“Keith came to me, and we spoke for about an hour,” Terry Smith tells PEOPLE. “I just told him to stay strong for his kids and not assume law enforcement has the answers and to push them.

“It was obvious Keith was torn up,” Terry says, “and I believe he was confident he’d get his wife back.”

Sherri’s case “brought back some very vivid memories and our hearts went out to Keith and his kids,” Terry says. “We know how it feels. That hopelessness and having nothing to go on is familiar.” Tera’s sister Kyra, was in the same grade as Sherri; Tera was a year older.

• Want to keep up with the latest crime coverage? Click here to get breaking crime news, ongoing trial coverage and details of intriguing unsolved cases in the True Crime Newsletter.

When Sherri was found, the Smiths were elated, Terry says: “I can’t tell you how thrilled we were. It’s bittersweet. We didn’t have that kind of outcome.”

Despite the strange surface similarities between Tera and Sherri’s disappearances, “there are notable differences,” Terry says.

While authorities are still piecing together why and by whom Sherri was abducted, Tera’s case is not so mysterious: Terry claims he knows who is responsible for his daughter vanishing — a man who has never been charged and denies involvement, but who remains a person of interest.

The End of a Love Affair Goes Wrong?

Terry tells PEOPLE that the night she disappeared, Tera had plans to meet with her married 29-year-old martial arts instructor and romantic interest, Charles Troy Zink, to end their relationship.

Zink had previously pleaded guilty to a felony rape charge in the early ’90s and served 300 days in jail, according to The Redding Herald Record.

Terry believes that by Tera breaking it off, Zink “saw this could go bad for him, and I think he killed her and disposed of the body.”

“This guy is a menace, a screwed-up guy,” Terry says.

He says he based his assumption about the planned breakup on Tera’s diaries and an unmailed letter found in her room after her disappearance.

“She tells him in the letter she knows she made a huge mistake, she never should have gotten involved with him, that she didn’t want to leave this life and hang her head in shame,” Terry says. “This letter was never delivered, and rather than give him the letter we believe she wanted to confront him in person to break it off.”

When Tera didn’t show up for work at 6 p.m. that August night, Terry and other family members went looking for her.

• Pick up PEOPLE’s special edition True Crime Stories: Cases That Shocked America, on sale now, for the latest on Casey Anthony, JonBenét Ramsey and more.

Terry says he was told during the search, by one of Tera’s friends, that his daughter was romantically involved with Zink. That night, he went to Zink’s house.

Terry says Zink wasn’t there, and he didn’t show up until 11:30 p.m. “Zink is an avid four-wheeler guy, he knows the back roads. He had five and a half hours to get rid of the evidence, and he’s been smart enough to keep his mouth shut,” Terry says.

Zink has denied involvement in Tera’s disappearance, according to The Redding Record Searchlight. But Sheriff Bosenko says he remains a person of interest, and the investigation is still open. “He refused to cooperate with investigators at the time,” Bosenko says.

Zink told Terry (and reportedly told authorities) that he picked up Tera near her home after she called him at work to borrow $2,000.

“He claims she was upset when he didn’t have it and drove her to a spot three miles from our house, dropped her off at a busy intersection, and then drove to Hang Glider Hill and prayed for five hours,” Terry says.

But he notes that of the thousands of tips called in after Tera disappeared, not one person saw her on the busy road.

‘It’s Time to Prosecute the Guy’

Authorities discovered that in the days after Tera’s disappearance, the tires on Zink’s vehicle, a Ford truck, had been replaced with ones in worse condition and the truck had been thoroughly cleaned, according to the Record Searchlight.

After Tera’s disappearance, Zink served a four-year prison sentence as a felon in possession of firearms, according to the Record Searchlight.

When PEOPLE contacted the California Department of Corrections and Rehabilitation for Zink’s criminal records, officials declined to release them.

“The Shasta County Sheriff’s Department will not authorize the release of any information about Troy Zink, citing an open investigation,” a spokeswoman for the department said in an email.

“This is an open investigation, which the law allows agencies to limit or disclose information about the case,” Sheriff Bosenko says.

When informed of the investigation’s status by email, Terry says that he isn’t aware of anything new in the case.

“I don’t get why something hasn’t budged in this many years,” he says. “I would love to see the police reopen the case and get back on it. It’s time to prosecute the guy. Everyone in the community thinks he’s the one to blame.”

Zink still lives in Redding, according Terry and public records. When reached by PEOPLE for comment on Terry’s accusations, Zink said, “Please hold,” and transferred the call to a voicemail.

Terry says Zink works with his father at the family coin business, Chuck’s Coins, in Redding, but he has not run into him in all these years.

“Zink is the only one who knows the whole story,” Terry says. “We believe in eternal justice, and he will be held accountable for what he’s done. I am saddened it’s not immediate. I can’t let him get off completely.”

• With reporting by CHRISTINE PELISEK