Anne Sullivan testified that she hadn’t told anyone of the teacher who had abused her in seventh grade until she came face-to-face with Christopher Kloman in the hallway of her son’s school more than 40 years later.

Sullivan, now in her mid-50s, said she was so sickened by the fear that the teacher might be abusing other girls that she broke her long silence and alerted the administration of Washington Episcopal School.

Kloman, 74, was sentenced to 43 years in prison Friday in a Fairfax County courtroom for molesting five girls, including Sullivan, at McLean’s elite Potomac School in the late 1960s and ’70s, when he was a teacher and administrator. Sullivan’s chance encounter in November 2011 and tip sparked the lengthy investigation and criminal proceeding that brought the decades-old abuse to light.

“As a mature woman, a lawyer and a mother, I was fed up,” Sullivan testified at the hearing. “I was more than fed up. One girl is too much. One generation is too much. . . . The girls at my son’s school were the exact same age I was when he assaulted me.”

Each of the five victims in the case gave harrowing accounts Friday of the sexual abuse they suffered at the hands of a man they trusted implicitly. The attacks lasted seconds or minutes, but they said the devastating effects rippled out over a lifetime. Sullivan and other women who were victims said they wanted to go public and agreed to be identified.

Christopher R. Kloman (Fairfax County Police)

Some testified that the exclusive school was alerted to Kloman’s assaults but did little to stop them. After the sentencing, the idea was echoed by nationally known lawyer Gloria Allred, who is representing all five women and called on the school to investigate the complaints and “do the right thing.” She did not elaborate.

Sullivan was the first to testify before a courtroom packed with Potomac School alumni and Kloman’s family and friends. She said Kloman invited her and a friend over to swim at his house after a seventh-grade field trip.

Sullivan was ecstatic. She testified that Kloman was a “fun and irreverent” teacher. But once in the pool, Kloman pulled her onto his lap, pinned her arms behind her back and thrust against her, she testified. Sullivan said Kloman held her so tightly his arms were like “lobster claws.”

She didn’t comprehend what was happening.

“Mr. Kloman is my teacher,” she recalled thinking. “He is really cool. . . . This has got to be okay.”

Laura Gill testified that Kloman pinned her down and assaulted her in the basement of his home while his family was upstairs. She was 14 at the time, and Kloman was an administrator at the Potomac School. He had invited her to play in a father-daughter tennis tournament.

Gill testified that she told her parents and a teacher about the abuse and that they alerted the administration. School officials sent Kloman for counseling, she said, and she was horrified that she had to continue to walk by his office.

“My sense of self-esteem had been crushed,” Gill said. “No one thought what he did was bad enough to help me.”

Late Friday, John Kowalik, the head of the Potomac School, said that the school takes the allegations “very seriously and will follow up on the issues raised. We look forward to the opportunity to speak with the victims and hear their concerns.”

Some of the women testified that they had been through years of therapy after the abuse. For decades, most never revealed what had happened.

“My private self lived with secrets that if anyone discovered them, they would know how wretched I was,” said the Rev. Jane Gould, who was molested in seventh grade. “I buried that little girl. She was not allowed to grow up.”

Kloman pleaded guilty to four counts of indecent liberties with a child younger than 14 and one count of abduction with intent to defile in August. He taught at the Potomac School from 1966 to 1994.

One woman testified that some girls at the Potomac School nicknamed him “the Wolf,” but family and friends said they had no inkling of that man. They testified that Kloman was a caring father, a great educator and a volunteer with Habitat for Humanity.

More than 90 people, including former ABC News anchor Charlie Gibson and Ken Starr, the special prosecutor who investigated the Whitewater matter during the Clinton presidency, wrote letters on Kloman’s behalf.

“It is a case almost Dostoyevskian,” Gibson wrote. “Chris has carried this guilt with him for years, and I can’t imagine how the knowledge that it would some day come out, as it inevitably would, must have eaten at his soul.”

Before he was sentenced, Kloman, in a green jail jumpsuit, rose to address the courtroom. As looked at his prepared remarks, he broke down crying and could not continue, so his attorney, Peter Greenspun, began reading them.

Eventually, Kloman regained his composure and apologized to the women — now with graying hair and reading glasses in some cases — whom he had abused as children so long ago.

“I can’t take any of it away,” Kloman said. “Please realize I did this and not you. I hope and pray you find some closure.”