The young teacher hung his head, avoiding eye contact. Yes, he had touched a fifth-grader's breast during recess. "I guess it was just lust of the flesh," he told his boss.

That got Gary C. Lindsey fired from his first teaching job in Oelwein, Iowa. But it didn't end his career. He taught for decades in Illinois and Iowa, fending off at least a half-dozen more abuse accusations.

When he finally surrendered his teaching license in 2004 — 40 years after that first little girl came forward — it wasn't a principal or a state agency that ended his career. It was one persistent victim and her parents.

Lindsey's case is just a small example of a widespread problem in American schools: sexual misconduct by the very teachers who are supposed to be nurturing the nation's children.

Students in America's schools are groped. They're raped. They're pursued, seduced and think they're in love.

An Associated Press investigation found more than 2,500 cases over five years in which educators were punished for actions from bizarre to sadistic.

There are 3 million public school teachers nationwide, most devoted to their work. Yet the number of abusive educators — nearly three for every school day — speaks to a much larger problem in a system that is stacked against victims.

Most of the abuse never gets reported. Those cases reported often end with no action. Cases investigated sometimes can't be proven, and many abusers have several victims.

And no one — not the schools, not the courts, not the state or federal governments — has found a surefire way to keep molesting teachers out of classrooms.

Those are the findings of an AP investigation in which reporters sought disciplinary records in all 50 states and the District of Columbia. The result is an unprecedented national look at the scope of sex offenses by educators — the very definition of breach of trust.

The seven-month investigation found 2,570 educators whose teaching credentials were revoked, denied, surrendered or sanctioned from 2001 through 2005 following allegations of sexual misconduct.

Young people were the victims in at least 1,801 of the cases, and more than 80 percent of those were students. At least half the educators who were punished by their states also were convicted of crimes related to their misconduct.

Beyond the horror of individual crimes, the larger shame is that the institutions that govern education have only sporadically addressed a problem that's been apparent for years.

"From my own experience — this could get me in trouble — I think every single school district in the nation has at least one perpetrator. At least one," says Mary Jo McGrath, a California lawyer who has spent 30 years investigating abuse and misconduct in schools. "It doesn't matter if it's urban or rural or suburban."

One report mandated by Congress estimated that as many as 4.5 million students, out of roughly 50 million in American schools, are subject to sexual misconduct by an employee of a school sometime between kindergarten and 12th grade. That figure includes verbal harassment that's sexual in nature.

Jennah Bramow, one of Lindsey's accusers in Cedar Rapids, Iowa, wonders why there isn't more outrage.

"You're supposed to be able to send your kids to school knowing that they're going to be safe," says Bramow, now 20. While other victims accepted settlement deals and signed confidentiality agreements, she sued her city's schools for failing to protect her and others from Lindsey — and won. Only then was Lindsey's teaching license finally revoked.

As an 8-year-old elementary-school student, Bramow told how Lindsey forced her hand on what she called his "pee-pee." She was asked by a school official how it felt and replied, "Bumpy." Then she drew a picture that showed how Lindsey made her touch him on the zipper area of his pants.

Lindsey, now 68, refused multiple requests for an interview. "It never occurs to you people that some people don't want their past opened back up," he said when an AP reporter approached him at his home outside Cedar Rapids.

That past, according to evidence presented in the Bramow's civil case, included accusations from students and parents along with reprimands from principals that were filed away, explained away and ultimately ignored until 1995, when accusations from Bramow and two other girls forced his early retirement. Even then, he kept his teaching license until the Bramows took the case public and filed a complaint with the state.

Like Lindsey, the perpetrators that the AP found are everyday educators — teachers, school psychologists, principals and superintendents among them. They're often popular and recognized for excellence and, in nearly nine out of 10 cases, they're male. While some abused students in school, others were cited for sexual misconduct after hours that didn't necessarily involve a kid from their classes, such as viewing or distributing child pornography.

They include:

— Joseph E. Hayes, a former principal in East St. Louis, Illinois. DNA evidence in a civil case determined that he impregnated a 14-year-old student. Never charged criminally, his license was suspended in 2003. He has ignored an order to surrender it permanently.

— Donald M. Landrum, a high school teacher in Polk County, North Carolina. His bosses warned him not to meet with female students behind closed doors. They put a glass window in his office door, but Landrum papered over it. Police later found pornography and condoms in his office and alleged that he was about to have sex with a female student. His license was revoked in 2005.

— Rebecca A. Boicelli, a former teacher in Redwood City, California. She conceived a child with a 16-year-old former student then went on maternity leave in 2004 while police investigated. She was hired to teach in a nearby school district; board members said police hadn't told them about the investigation.

The overwhelming majority of cases the AP examined involved teachers in public schools. Private school teachers rarely turn up because many are not required to have a teaching license and, even when they have one, disciplinary actions are typically handled within the school.

Two of the nation's major teachers unions, the American Federation of Teachers and the National Education Association, each denounced sex abuse while emphasizing that educators' rights also must be taken into account.

"Students must be protected from sexual predators and abuse, and teachers must be protected from false accusations," said NEA President Reg Weaver, who refused to be interviewed and instead released a two-paragraph statement.

The United States has grown more sympathetic to victims of sex abuse over recent decades, particularly when it comes to young people. Police have made pursuing Internet predators a priority. People convicted of abuse typically face tough sentences and registry as sex offenders.

Even so, sexually abusive teachers continue to take advantage, and there are several reasons why.

For one, many Americans deny the problem, and even treat the abuse with misplaced fascination. Popular media reports trumpet relationships between attractive female teachers and male students.

"It's dealt with in a salacious manner with late-night comedians saying 'What 14-year-old boy wouldn't want to have sex with his teacher?' It trivializes the whole issue," says Robert Shoop, a professor of educational administration at Kansas State University.

"In other cases, it's reported as if this is some deviant who crawled into the school district — 'and now that they're gone, everything's OK.' But it's much more prevalent than people would think."

The AP investigation found efforts to stop individual offenders but, overall, a deeply entrenched resistance toward recognizing and fighting abuse. It starts in school hallways, where fellow teachers look away or feel powerless to help. School administrators make behind-the-scenes deals to avoid lawsuits and other trouble. And lawmakers shy from tough state punishments or any cohesive national policy for fear of disparaging a vital profession.

That only enables rogue teachers, and puts kids who aren't likely to be believed in a tough spot.

In case after case the AP examined, accusations of inappropriate behavior were dismissed. One girl in Mansfield, Ohio, complained about a sexual assault by teacher Donald Coots and got expelled. It was only when a second girl, years later, brought a similar complaint against the same teacher that he was punished.

And that second girl also was ostracized by the school community and ultimately left town.

Unless there's a videotape of a teacher involved with a child, everyone wants to believe the authority figure, says Wayne Promisel, a retired Virginia detective who has investigated many sex abuse cases.

He and others who track the problem reiterated one point repeatedly during the AP investigation: Very few abusers get caught. They point to several academic studies estimating that only about one in 10 victimized children report sexual abuse of any kind to someone who can do something about it.

Teachers, administrators and even parents frequently don't, or won't, recognize the signs that a crime is taking place.

"They can't see what's in front of their face. Not unlike a kid in an alcoholic family, who'll say 'My family is great,"' says McGrath, the California lawyer and investigator who now trains entire school systems how to recognize what she calls the unmistakable "red flags" of misconduct.

In Hamburg, Pennsylvania, in 2002, those "red flags" should have been clear. A student skipped classes every day to spend time with one teacher. He gave her gifts and rides in his car. She sat on his lap. The bond ran so deep that the student got chastised repeatedly — even suspended once for being late and absent so often. But there were no questions for the teacher.

Heather Kline was 12, a girl with a broad smile and blond hair pulled back tight. Teacher Troy Mansfield had cultivated her since she was in his third-grade class.

"Kids, like, idolized me because they thought I was, like, cool because he paid more attention to me," says Kline, now 18, sitting at her mother's kitchen table, sorting through a file of old poems and cards from Mansfield. "I was just like really comfortable. I could tell him anything."

He never pushed her, just raised the stakes, bit by bit — a comment about how good she looked, a gift, a hug.

She was sure she was in love.

By winter of seventh grade, he was sneaking her off in his car for an hour of sex, dropping in on her weekly baby-sitting duties, e-mailing about what clothes she should wear, about his sexual fantasies, about marriage and children.

Mansfield finally got caught by the girl's mother, and his own words convicted him. At his criminal trial in 2004, Heather read his e-mails and instant messages aloud, from declarations of true love to explicit references to past sex. He's serving up to 31 years in state prison.

The growing use of e-mails and text messages is leaving a trail that investigators and prosecutors can use to prove an intimate relationship when other evidence is hard to find.

Even then, many in the community find it difficult to accept that a predator is in their midst. When these cases break, defendants often portray the students as seducers or false accusers. However, every investigator questioned said that is largely a misconception.

"I've been involved in several hundred investigations," says Martin Bates, an assistant superintendent in a Salt Lake City school district. "I think I've seen that just a couple of times ... where a teacher is being pursued by a student."

Too often, problem teachers are allowed to leave quietly. That can mean future abuse for another student and another school district.

"They might deal with it internally, suspending the person or having the person move on. So their license is never investigated," says Charol Shakeshaft, a leading expert in teacher sex abuse who heads the educational leadership department at Virginia Commonwealth University.

It's a dynamic so common it has its own nicknames — "passing the trash" or the "mobile molester."

Actions taken against teachers vary from state to state, but the AP found the number of state actions against sexually abusive teachers rose steadily, to a high of 649 in 2005. More states now require background checks on teachers, fingerprinting and mandatory reporting of abuse, though there are still loopholes and a lack of coordination among districts and states.

U.S. Supreme Court rulings in the last 20 years on civil rights and sex discrimination have opened schools up to potentially huge financial punishments for abuses, which has driven some schools to act.

And the National Association of State Directors of Teacher Education and Certification keeps a list of educators who've been punished for any reason, but only shares the names among state agencies. The uncoordinated system that's developed means some teachers still fall through the cracks and move on to other teaching jobs.

Victims also face consequences when teachers are punished.

In Pennsylvania, after news of teacher Troy Mansfield's arrest hit, girls called Kline, his 12-year-old victim, a "slut" to her face. A teacher called her a "vixen." Friends stopped talking to her. Kids no longer sat with her at lunch.

So, between rumors that she was pregnant or doing drugs and her own panic attacks and depression, Kline bounced between schools. At 16, she ran away to Nashville.

"I didn't have my childhood," says Kline, who's back home now, working as a grocery cashier and hoping to eventually go to nursing school. "He had me so matured at so young.

"I remember going from little baby dolls to just being an adult."

The courts dealt her a final insult. A federal judge dismissed her civil suit against the school, saying administrators had no obligation to protect her from a predatory teacher since officials were unaware of the abuse, despite what the court called widespread "unsubstantiated rumors" in the school. The family is appealing.