Peggy Drexler is the author of " Our Fathers, Ourselves: Daughters, Fathers, and the Changing American Family " and " Raising Boys Without Men ." She is an assistant professor of psychology at Weill Medical College of Cornell University and a former gender scholar at Stanford University. The opinions expressed in this commentary are hers.

(CNN) Five weeks from the day she vanished after a friend dropped her off at a Shoney's near her rural Tennessee home, 15-year-old high school freshman Elizabeth Thomas was found Thursday in a cabin in Siskiyou County, California. She was with 50-year-old Tad Cummins, her former forensics teacher, police said.

That the break in the case came from a bystander nowhere near her hometown is notable, considering those in Elizabeth's own town of Culleoka had arguably failed to do their part to prevent the crime from happening in the first place.

Although a timeline of events shows that suspicion of the teacher-student relationship had been building for months, mostly inaction ruled until the pair left town mid-March. In January, a classmate of Elizabeth's reported seeing the two kissing in a classroom. Cummins described his relationship with Elizabeth to other students, according to school investigative files , as "a close and best friend." Teachers reported seeing Elizabeth in Cummins's classroom "a lot," with one even noticing that the student had moved her desk closer to the teacher's.

Over that time, the school says it took several steps to address the situation -- opening an investigation on January 25, removing Elizabeth from Cummins' class, monitoring the teacher to be sure students weren't in his classroom when they weren't supposed to be.

But they neglected to alert Elizabeth's father about the alleged kiss, according to the family's lawyer ; Thomas learned about the allegations more than a week later from a detective with the Maury County Sheriff's Department, he said. After that, Elizabeth told her father, he said, that she was still in Cummins' class, although the school district said in a February 8 internal memo provided to CNN, that she had been removed, leaving Anthony Thomas to wonder when and if she was removed at all.

They did not suspend Cummins until close to mid-February. A subsequent look at Cummins's work email showed that he and Elizabeth had been communicating, often in inappropriate language, for months -- and yet that had gone undetected, as well.

Although laws differ from state to state, there's a reason teacher-student relationships are frowned upon, if not outright illegal. By nature, they are not consensual, even if the students involved think they are, and often they do. Some students may even think they're the ones who pursued the relationship -- that they "asked for it." They may like the attention, or the power they think the relationship gives them.

But what's actually happening, in every case, is that the student is being groomed to accept what is, most definitely, a form of sexual abuse. Whether it's by promising access to things a teenager doesn't have, but would like to -- money, a car, sexual knowledge -- or attention a student lacks, in every case the adult is in charge and manipulating the situation.

In this case, Cummins reportedly told students at the school that Elizabeth "had been through a lot and suffered an abusive home life." Elizabeth told authorities that she went to Cummins when she needed to talk -- and, of course, he was always there. And while teenagers are well known for keeping secrets, it's important to note that responsibility also falls to Elizabeth's family. Her father apparently knew, and was alarmed by, Cummins' attentions to his daughter. Could he not have demanded that the school remove Cummins?

This is why schools need to bear the responsibility of defining what's not appropriate when it comes to teacher-student interactions -- making those rules clear to teachers, students, and parents -- and outlining clear consequences for what happens when boundaries are crossed. Schools need to make it easy for victims to come forward, and to recognize they're victims at all.

According to a recent survey by the National Sexual Violence Resource Center, many people don't even know what constitutes sexual assault, and younger adults are even less aware than those over the age of 35. For example, while most know that unwanted touching and sexual intercourse without a partner's consent are considered assault, fewer understand that watching someone in a private act without their consent, or verbal harassment, are forms of assault, too.

It's also critical for schools to encourage bystander intervention, educating students about reporting things they see and about the importance of reaching out to the suspected victim directly. Students who feel alienated from their peers may be more likely to fall victim to abuse at the hands of teachers.

Reports suggest that the teachers and students in Elizabeth's school were gossiping about Elizabeth and Mr. Cummins -- and fact, it was a student who first went to the administration to report that she'd seen the two kissing.

While the school's internal investigation alludes to a discussion in which Cummins and Elizabeth were "instructed to have no contact," it's unclear whether a counselor, a trusted adult, tried to engage the girl about the nature of her contact with Cummins.

Cummins was arrested on kidnaping charges, but it's not clear that those charges will stick. Tennessee state law allows children older than 12 to decide whether to leave their families, unless they have been forced to or threatened.

Authorities at the scene of the rescue described Elizabeth as "alternating between 'stoic' and 'emotional,'" with one officer stating that "the two obviously have a relationship." It's likely Elizabeth won't know whether she's been abused or not; she'll need adult help. Given all those who have already failed her, we can only hope they'll step up now.