Leonard accessed the Zetaware site from a Sprint wireless network at Houston's George Bush Intercontinental Airport, located near Zetaware's headquarters, the plea agreement states.

In a separate case, Platte River Associates is also facing charges of "trading with the enemy," for allegedly allowing its software to be used to evaluate oil and gas development opportunities off the shore of Cuba, which is under a U.S. trade embargo. "The company has expressed an interest in pleading guilty," in that case, although no plea has been accepted by the judge, according to Jeffrey Dorschner, a spokesman for the United States Attorney's office prosecuting the two cases.

Leonard and his attorney did not return calls seeking comment for this story.