Is the US Attorney in Manhattan bucking for the Well, Duh! Award?

Rebecca Davis O'Brien, Christopher M. Matthews and Farnaz Fassihi report in the WSJ:

A former president of the United Nations General Assembly and five others were accused Tuesday of engaging in a bribery scheme, part of what federal authorities said was a wider probe into corruption in the top ranks of the international body.

"We will be asking, is bribery business as usual at the U.N.?" said Preet Bharara, the U.S. attorney in Manhattan, at a news conference announcing the charges.

The more difficult question comes later in the story:

Messrs. Ashe and Lorenzo could be shielded by diplomatic immunity in certain circumstances, but the complaint said they can be prosecuted for crimes outside the scope of their official positions.

That is not my understanding of diplomatic immunity, but I don't pretend any expertise on the subject.