In a quiet living room, a Maryland woman, now a high school teacher, recalled an unwanted encounter she had with a male teacher when she was just 17.
"He wanted to give me a kiss, and the kiss evolved into a deeper kiss," she says. "I was confused because I'd never been in a situation like this. I was angry at the time, and repulsed."
The teacher, who wants to remain anonymous, says the man was twice her age. She says he approached other girls as well.
"My gut told me it needed to stop. It's horrific for a teacher to take advantage of the people who are supposed to trust them," she says.
Her father later approached the man and told him to stay away. The man, she says, was never charged with a crime but was asked to leave the school.
Reports of teachers who make advances toward or abuse children are a cause of concern for parents.
"You assume you take your child to school and there is a teacher there, a well-behaved teacher, and sometimes you find the opposite", says Germantown resident Jennifer Kerchaert.
ABC7 News has created a photo gallery of once-trusted educators who are accused of harming students. The charges range from internet solicitation of a child to possession of child pornography and sexual contact with a student.
"I think there needs to be more screening, more background checks," said Brenda Jones, a Montgomery County mother of five children. She wonders if a pre-hire polygraph test for teachers would keep predators out.
"I know I wouldn't have a problem taking one if it was required for my job," she says. "It's a different world, a different time."
"'They should be like role models, really," says Raphael Alvarez, a retired federal worker who's gone through numerous background checks and has been polygraphed.
"When you have something like this, it makes you wonder, how did they get through the system. Were they not checked out?" he asks.
Metro area school districts typically conduct fingerprint and criminal background checks through the FBI, state police, and Child Protective Services.
Should teachers should be given lie detector tests? Take the ABC7 poll.
D.C. Public Schools does another background check two years after a teacher is hired. Montgomery County Schools, among others, is supposed to be informed if a current employee is arrested on criminal charges.
But no district in the D.C. metro area conducts polygraphs, according to inquiries by ABC7.
"Polygraphs are pretty expensive, and you have something like 11,000 teachers in Montgomery County," says Rockville resident Amy Hartley. "I guess that would be a pretty expensive proposition."
One school district spokesman said that polygraphs are pricey. Examiners charge $400 or more per session.
Kristen Anderson, a former police chief now with the Center for Missing and Exploited children, says there are people who can "beat" a polygraph test, but the machines are fairly reliable.
"It will lead to disclosure, but it's not a guarantee," she says.
Anderson brings up a point especially troubling to many parents - that a pedophile, with no criminal record, can fly under the radar.
"We know they're out there," she says. "If most of these perpetrators have never been caught, they're not going to show up in a criminal history check."
The Center's research shows there are nearly 740,000 registered sex offenders across the U.S.
"The vast majority of people who set out to work with children, who want to work with children, are there for all the right reasons. But every now and then, there's one who isn't," Anderson says.
She says she's sympathetic to the money issues but says a polygraph can uncover what records don't show.
"It really provided motivation for people to disclose information that they might not disclose otherwise," she says. "We would have people coming forward with information that wouldn't come up in any portion of the testing process."
Virtually all the school districts ABC7 contacted say they have no plans to start polygraph testing.
The above-mentioned teacher was victimized when she was 17. She says polygraphs could be a firewall to keep pedophiles away from schools. But she wonders about reliability and cost.
Still, she hopes that by speaking out, others will avoid what she experienced.
"I don't understand why people think they can take advantage of other people in situations like that," she says. "They'll take the innocence of some child. For somebody to be robbed of that is criminal."