The former head of security for a Pentagon agency that defends the country from nuclear and biological attacks was indicted on Friday for allegedly conspiring to steer large government contracts to a company that he helped start, according to federal court documents.

James E. Wright, the ex-chief of the Security and Counterintelligence Directorate for the Defense Threat Reduction Agency at Fort Belvoir, and John D. Villanueva, a U.S. Department of Defense contractor, were charged by a federal grand jury in Alexandria with conspiracy and committing an act affecting personal financial interest.