I predict an “I was conducting my own sting” defense:

WASHINGTON — A Duke University official has been arrested and charged with offering his adopted 5-year-old son for sex.

Frank Lombard, the school’s associate director of the Center for Health Policy, was arrested after an Internet sting, according to the FBI’s Washington field office and the city’s police department.

According to an affidavit by District of Columbia Police Det. Timothy Palchak, an unnamed informant facing charges in his own child sex case led authorities to Lombard.

Authorities said that Lombard tried to persuade a person — who he did not know was a police officer — to travel to North Carolina to have sex with Lombard’s child.