The teacher told one student that he wanted to show her slides of Kenya. He told another that he needed to talk to her about alleged cheating on her math homework. Another he hired to clean his home.

In each of those cases, in the 1960s and ’70s, Christopher Kloman isolated a girl so he could touch her inappropriately. Now 74, the former teacher at the Potomac School in McLean pleaded guilty Thursday in Fairfax County Circuit Court to four counts of indecent liberties with a child under 14 and one count of abduction with intent to defile. The charges involved four victims.

All of the crimes took place decades ago, when Kloman was an instructor and sports coach at the prestigious private school. They came to light late in 2011 when a former student contacted authorities after encountering Kloman at the Washington Episcopal School in Bethesda, where her daughter is a student, prosecutors said. She told police that she had been molested by Kloman when she was 12.

The Washington Post generally does not identify victims of sexual assault.

The investigation took more than a year, in part because of the difficulty in tracking down victims after so many years, prosecutors said. There is no statute of limitations on felonies in Virginia.

Before contacting police, the woman called Kloman to confront him, prosecutors said Thursday. The retired teacher said he did not remember the incident but had no reason to think she was lying, they said. He was sorry for what he had done, he told her.

Kloman gave a similar statement when contacted by police. And he went on to acknowledge similar transgressions involving other students at the school, writing authorities a detailed letter of apology, prosecutors said. He then called police back to say that he had remembered two more incidents. The woman who first contacted police was the first child, he said; in all, he estimated that he molested girls “less than 10 times” from 1966 to 1985.

In almost every instance, he told police, he lured a child to his home or a friend’s home and held her against his body, authorities said.

Prosecutors said at least two of the girls had told their parents about the molestation. One girl’s parents told the school’s headmaster, they said, and Kloman was told to get counseling. Another girl’s mother simply laughed at her, saying she must have “misconstrued” the situation.

Kloman was a family friend.

One former student contacted him 20 years later, asking him to pay for the therapy she was undergoing as a result of the molestation, prosecutors said. He sent her $4,000 and an apology.

Kloman told police that he was “ashamed, horrified, and disgusted with himself,” prosecutors said. He did not speak at Thursday’s hearing, which at least one victim attended, except to answer simple questions from the judge.

According to the Potomac School, Kloman taught there from 1966 to 1994. School officials said they had cooperated with local authorities and were told that the abuse by Kloman occurred from the mid-1960s to the early ’80s.

The person listed as head of school at that time period has died.

“The Potomac School community is saddened by this news, and our hearts and thoughts are with the victims,” said H. Lawrence Culp Jr., head of the school’s Board of Trustees.

Over objections from Kloman’s attorney, Judge Jan L. Brodie on Thursday allowed prosecutors to provide information about incidents that were not part of the guilty plea. The additional incidents included intercourse with a 17-year-old and several instances of intercourse with a 14-year-old, but the timing is not clear. Those incidents will be relevant at sentencing, the judge ruled.

Kloman’s plea to the charge of abduction with intent to defile was an Alford plea, which means that he does not admit guilt but concedes that prosecutors have enough evidence to obtain a conviction.

Kloman is scheduled to be sentenced in October, and there is no agreement with prosecutors on sentencing.

When the hearing was over, Kloman didn’t ask to be released on bond before sentencing. He handed his blue sports coat to his family and was led off to jail in handcuffs.

“He accepts full responsibility,” defense attorney Peter Greenspun said.

“He felt that it was appropriate to make that clear.”