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 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.

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.

The findings draw obvious comparisons to sex abuse scandals in other institutions, among them the Roman Catholic Church. A review by America’s Catholic bishops found that about 4,400 of 110,000 priests were accused of molesting minors from 1950 through 2002.

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.

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.

The majority of cases the 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.

The United States has grown more sympathetic to victims of sex abuse over recent decades, particularly when it comes to young people. Laws that protect children from abusers bear the names of young victims. 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 who has written a book aimed at helping school districts identify and deal with sexual misconduct.

“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 in state capitals and Congress, 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.

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.

Laws in several states require that even an allegation of sexual misconduct be reported to the state departments that oversee teacher licenses. But there’s no consistent enforcement, so such laws are easy to ignore.

In the Iowa case, Lindsey agreed to leave without fighting when his bosses kept the reason for his departure confidential. The decades’ worth of allegations against him would have stayed secret, if not for Bramow.

Across the country, such deals and lack of information-sharing allow abusive teachers to jump state lines, even when one school does put a stop to the abuse.

While some schools and states have been aggressive about investigating problem teachers and publicizing it when they’re found, others were hesitant to share details of cases with the AP – Alabama and Mississippi among the more resistant. Maine, the only state that gave the AP no disciplinary information, has a law that keeps offending teachers’ cases secret.

Meanwhile, the reasons given for punishing hundreds of educators, including many in California, were so vague there was no way to tell why they’d been punished, until further investigation by AP reporters revealed it was sexual misconduct.

And in Hawaii, no educators were disciplined by the state in the five years the AP examined, even though some teachers there were serving sentences for various sex crimes during that time. They technically remained teachers, even behind bars.

Elsewhere, there have been fitful steps toward catching errant teachers that may be having some effect. 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.