A McLean man has been charged with sexually assaulting several students while he taught at the Potomac School during the 1960s, according to authorities.

Christopher R. Kloman, 73, was arrested Friday following a yearlong investigation into reports that he molested a 12-year-old student 43 years ago. The woman first reported the incident in November 2011 after discovering Kloman was teaching at the Washington Episcopal School in Bethesda.

Police believe Kloman, who last taught at the Potomac School in 1994, was a substitute at Washington Episcopal, according to spokesman Officer Eddy Azcarate.

The past year's investigation revealed three other victims, all former students who were between the ages of 12 and 14 at the time of the alleged offenses, which all took place in 1968 and 1969, police said.

Detectives are still investigating the case -- there are other incidents that occurred during 1960s and '70s still under investigation that raised eyebrows, and may or may not result in more charges, according to Azcarate.

There is no indication that any incidents have occurred since the early 1980s, he said.

Kloman was charged with three felony counts of indecent liberties and one count of abduction with intent to defile. Kloman was charged under the law as it was written in the 1960s -- if he'd been charged under today's laws, Kloman likely would have been charged with aggravated sexual battery instead of indecent liberties, according to Azcarate.

The old code is "part of the reason why the investigation has and is taking such a long time," Azcarate said.

None of the victims were willing at this time to speak to the media, he said.