The arrest of a man accused of stealing Goldman Sachs’ trading software may only be the tip of the iceberg at Teza Technologies, according to Citadel Investment Group.

The Chicago hedge fund giant yesterday sued Teza and its three founders—all former executives at Citadel—alleging they violated their non-compete agreements. What’s more, Citadel alleges that Teza’s hiring of Sergey Aleynikov—arrested last week just a day after he started at Teza for allegedly stealing software from Goldman, where he had worked as a computer programmer—“create a substantial risk that they have stolen, or may be planning to steal, Citadel’s proprietary code.”

“This is a case of industrial espionage,” Citadel alleged in its complaint, filed in Chicago state court. Teza claims to be a so-called “formative” firm that does not trade or invest. A lawyer for Teza said that his clients did not violate any non-compete agreements or steal any technology from Citadel.

Citadel has asked the court to ban Misha Malyshev, Jace Kohlmeier and Matt Hinerfeld from conducting any business through Teza until their non-compete agreements expire.