Durham, N.C. — A former Duke University employee pleaded guilty in Washington, D.C., Thursday to a federal child sex charge, authorities said.

Frank M. Lombard, 42, of 24 Indigo Creek Trail in Durham, was arrested in June after authorities said Washington police caught him in a sting operation.

He was fired from his position as associate director of the Center for Health Policy at Duke in July and has been in a D.C. jail since August.

In court documents, an undercover member of the Washington Metropolitan Police Department described an online chat in which someone named "F.L." invited him to Durham to have sexual contact with his adopted 5-year-old son.

The officer made contact with "F.L" after an informant told FBI agents that he saw a man called “cooper2” perform sex acts on a young African-American child via online chats on multiple occasions. The informant's description of "cooper2" corresponded with the description of Lombard.

Lombard was charged with attempting to induce someone to cross state lines to engage in a sexual offense. He pleaded to sexual exploitation of a minor, a charge which carries a maximum sentence of 30 years in prison. After a sentencing hearing in March, he will be transferred to federal prison, authorities said.