FBI agents have executed a search warrant at the Northern Illinois University police station. The station was locked down as agents gathered documents and information, but neither the FBI nor the state police would say what the investigation was about, except to say that no arrests were made. It's not clear whether the search is connected to last month's firing of campus police chief Donald Grady in the wake of the department's mishandling of a rape case. Grady himself had asked for FBI assistance in his investigation of the conduct of two high-ranking university administrators.