The victim, only identified by her initials J.S., was allegedly molested by Gardner Dunnan (above) in the fall of 1986 when he was the headmaster at New York's prestigious Dalton School

The former head of New York's prestigious Dalton School has been accused in a lawsuit of sexually assaulting a 14-year-old girl who lived with him and his wife while attending the school in the 1980s.

The victim, only identified by her initials J.S., was allegedly molested by Gardner Dunnan in the fall of 1986 at his homes in New York and New Jersey.

The lawsuit was filed on Thursday in federal court in Newark, New Jersey.

It alleges that Dunnan repeatedly touched the girl without her consent, fondling her breasts, sticking his tongue in her mouth, disrobing and groping her, laying on top of her and thrusting his genitals against her.

The girl's parents had divorced and she was living with her father in Brooklyn in 1986 when they met Dunnan through the father's girlfriend.

Dunnan allowed the girl to be admitted to the school without going through a formal application process, the lawsuit states.

Given she couldn't afford the tuition, the lawsuit states that the girl was allowed to live with Dunnan and his wife provided she helped them with their newborn baby at their apartment near the school.

The girl also traveled to their home in Ocean County, New Jersey.

She claims Dunnan allegedly attacked her on four occasions between September 1986 and January 1987.

Dunnan had allowed her to be admitted to the elite school (above) without going through the formal application process and offered accommodation at his home if she helped his family, lawsuit states

The lawsuit states that Dunnan's then-wife asked the girl to leave their home shortly after he allegedly assaulted her.

The girl then transferred schools and suffered from depression and anxiety in the years since the alleged abuse, according to the suit.

She only began to realize the depth of the harm it caused after sexual assault allegations against movie producer Harvey Weinstein and other powerful men were publicized, the suit states.

Dunnan was headmaster at the Upper East Side school from the mid-1970s until 1997 when news of his affair with a married female teacher became known.

The elite school has educated a number of the rich and famous, including journalist Anderson Cooper, actresses Claire Danes and Tracee Ellis Ross, and actor Chevy Chase.

Tuition at the school is now $40,000.

The suit contends the prestigious school 'knew or should have known that Dunnan engaged in acts of inappropriate, abusive, and/or harmful behavior toward individuals over whom he had power or control.'

The suit seeks unspecified damages for alleged child sexual abuse, battery and intentional infliction of emotional distress by Dunnan, and negligent hiring, retention and supervision by Dalton.

She filed the lawsuit in New Jersey because unlike New York her claims are within the statute of limitations.

Dunnan's LinkedIn account lists several positions at schools in the New York City area in the years since he left Dalton.

It lists him currently as an independent college admissions counselor.

Dunnan didn't immediately respond to requests for comment. A phone message left with at the school wasn't immediately returned.