NEWARK, N.J. — The former head of New York's prestigious Dalton School was accused in a lawsuit Thursday of sexually abusing a 14-year-old girl who lived with him and his wife while attending the school in the 1980s.

The suit filed in federal court in Newark, New Jersey, accused Gardner Dunnan of molesting the girl in the fall of 1986. The woman, identified in the lawsuit by her initials, claimed the abuse occurred at Dunnan's homes in New York and New Jersey.

Dunnan "repeatedly touched J.S. 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 lawsuit alleged.

The suit contends Dalton "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."

Dunnan denied the allegations.

"During a career spanning more than 55 years in education I have never mistreated a student or previously been accused of doing that, and am heartbroken about these false accusations," he wrote in an email.

Through a spokeswoman, the school said it became aware of the lawsuit Thursday. "We take these issues very seriously and support any victim of sexual abuse," the school said in a statement.

Dunnan was headmaster from the mid-1970s until 1997, when news reports quoted Dunnan saying he was stepping down because of school officials' concerns with his leadership and personal life.

According to the lawsuit, 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 girl lived with Dunnan and his wife and helped them with their newborn baby at their apartment near the school, and also traveled to their home in Ocean County, New Jersey, according to the lawsuit.

The suit contends the girl has suffered from depression and anxiety in the years since the alleged abuse, and 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.

That "reasonable discovery of her injuries" occurred less than two years ago, keeping the claims within the statute of limitations, the suit said.

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.

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.