Where is Suzanne Lyall? 25 years after college student vanished, her mom isn't giving up

On the night of March 2, 1998, a 19-year-old college sophomore named Suzanne Lyall left work at a mall and took the bus back to school at the State University of New York -- Albany.

She got off the bus by campus around 9:25 p.m. to walk back to her dorm.

She has never been seen since.

For Suzanne Lyall’s mother, Mary Lyall, her mysterious disappearance has left a haunting hole in her heart that’s never been filled. But she channeled that pain into action, advocating for missing persons across the nation as she waits to find out what happened to her beloved youngest child.

Where is Suzanne?

Suzanne "Suzy" Lyall grew up in Ballston Spa in upstate New York with her parents and two doting siblings. Suzanne’s sister, Sandy, was nine years older than her, and her brother, Steve, was 12 years older.

"They fought over who was gonna have her sleep in their room at night when she was an infant," Mary Lyall told ABC News.

"When Suzy started kindergarten, [Steve] started his first year in college. And he would come back almost every weekend and take Suzy all sorts of places," Lyall said. "He couldn’t stand being without her."

Suzanne loved to sew and write poetry, her mom said, but her biggest passion was computers. When she was about 10 years old, her dad bought an old Commodore computer.

"Nobody knew what a computer was, basically. And the Commodores back then, all they did was add and subtract -- and really slowly at that. But she was really curious about the computer," Lyall said. "By the time she was 12 years old, she was taking the computer apart and rebuilding it. She was very fascinated by the fact that she could dial up all these local … bulletin boards and talk to other people over the computer."

"I think she felt like this was a good outlet for her -- she always said she was shy," Lyall said.

Suzanne decided to study computer science. In the fall of 1996, she enrolled as a freshman at SUNY Oneonta.

"But the [SUNY Oneonta] teachers were just basically starting to learn a little bit about computers -- Suzy had already graduated past what they had learned," her mom said. "So that’s why she decided to come to the University at Albany, hoping she could get a little more advanced lessons."

Suzanne transferred to the University at Albany in the fall of 1997.

On the night of March 1, 1998, Suzanne called her mother to wish her a happy birthday. She apologized for not coming home to celebrate that night, but said she wanted to focus on midterms.

On March 2, Suzanne went to work at her part-time job at a computer software store at the Albany-area Crossgates Mall. After work, Suzanne caught a Capital District Transit Authority bus back to campus, the New York State Police said.

She got off the bus at the Collins Circle stop at SUNY Albany at about 9:25 p.m. She was heading to her dorm, state police said, which was only about 900 to 950 feet away, according to the university.

But she never made it back.

Mary Lyall said Suzanne’s boyfriend called her on March 3 and said: "Did you know Suzy didn’t come back to her room last night?"

Suzanne’s father, Doug Lyall, quickly jumped in the car and raced to the university.

Her room didn’t look disturbed, Mary Lyall said. Her glasses were there and her hairdryer was left on the bed.

The state police launched an investigation and started asking the family for information.

Police won't say if Suzanne's boyfriend has been ruled out as a suspect.

"Multiple interviews have been conducted," a state police spokesperson told ABC News. "Given the status on the investigation NYSP will not disclose who has or has not been ruled out as people of interest in this investigation."

In the first month of the investigation, authorities searched over 400 acres for Suzanne, including campus, the Crossgates Mall and local bike paths, state police said.

'You're not alone in this fight'

After a few months, Mary Lyall said the case seemed to go cold. The Lyalls felt they had to become their own investigators, and the family started pouring their energy into searching for answers. New York State Police said its troopers "began investigating on the day we were notified of her disappearance, and that investigation is ongoing."

"My husband and I tried to do everything we could think of to find our daughter," Lyall said.

Soon, their focus widened from Suzanne to missing persons nationwide.

On any given day, there are about 90,000 active missing person cases in the United States’ National Crime Information Center, according to the National Missing and Unidentified Persons System.

"We just decided that this was not the way it should be, because there are so many other families out there that have a missing person in their life," she said. "We needed to let them know the little bit we had learned that far."

In 2001, three years after Suzanne vanished, Mary and Doug Lyall founded the Center for Hope, a nonprofit that provides resources for families of missing persons.

"When somebody goes missing in your family, you think to yourself, 'It's just me. Why did this happen to me?'" she said. The Center for Hope "brought a lot of people together. When you’re sitting seeing in the same room and looking around at all these other faces … You’re not alone in this fight."

The Lyalls looked for creative ways to share missing persons’ stories.

They created a playing card program where 52 pictures of missing people were printed on a deck of cards, and the decks were distributed to New York state jails.

"I’m really proud of that," she said.

They even produced coasters featuring photos of missing Albany-area people and distributed them to local restaurants and bars, she said.

The Lyalls also pushed for legislative changes.

"Suzanne's Law," signed by President George W. Bush in 2003, keeps law enforcement from imposing a waiting period before accepting missing persons reports for young adults between the ages of 18 and 21.

"When a child goes missing, they automatically go into the National Center for Missing and Exploited Children and get a lot of services. But if you just turned 18, there’s nothing, there’s a gray area," Lyall said. "We just decided that we have to raise this age."

In 2007, "The Suzanne Lyall Campus Security Act" was signed into federal law, requiring colleges to create written safety plans with local law enforcement.

"Even though we were helping other people, we were helping ourselves along the way," Lyall said, because their advocacy "kept Suzy’s name out there."

'I'm still hoping'

Mary Lyall’s husband, Doug, died in 2015.

But Mary Lyall still lives in the house where they raised their three children. Last year marked 50 years there. She’s kept Suzanne’s room mostly the same, including the collection of bunnies she’d sew and sell as a teen.

And at the university where the 19-year-old vanished, "Suzanne Lyall has never been forgotten," a spokesperson for the University at Albany told ABC News.

The university’s police department keeps Suzanne Lyall’s photo on its bulletin board.

The university said its police department "continues to share information about the case with the State Police as it becomes available."

The university added, "One of the most powerful legacies of Suzanne’s disappearance is the example set by her family, who not only have never given up the search for Suzanne but became tireless advocates and sources of hope and support for other families of missing persons."

As the years passed, and the case file was passed from one generation of New York State Police officers to the next, Mary Lyall said she often befriended the officers assigned to her daughter’s case, even attending some of their weddings and retirement parties.

A state police spokesperson told ABC News the investigation is ongoing and remains categorized as a missing persons case.

"The New York State Police continues to investigate any tips or leads as they become available," the police told ABC News last month.

Lyall said she’s never given up hope.

"Every time we went on a conference, everywhere we went, I'd be sitting in that airport looking at every single face," she said. "Wondering if the next one that's gonna walk up is her."

"I’m still hoping," she said.

ABC News' Jeff Swartz and Jason Potere contributed to this report.