David C. Cox, 42, who learned Russian, trekked to the then-Soviet Union for a brief exchange program in college and later wrote two books probing that nation's military and security concerns, died Aug. 31. His body was found under the Q Street Bridge in Rock Creek Regional Park.

The medical examiner's office said a cause of death still is pending, but police said they suspect it was suicide.

Mr. Cox lived in Silver Spring briefly in the mid-1980s but since then in the District.

Mr. Cox had been an assistant professorial lecturer at George Washington University since 1991, the year he received his doctorate there in political science with a major in international politics.

After completing his dissertation on the Soviet invasion of Afghanistan, Mr. Cox started writing his first book, "Retreating From the Cold War: Germany, Russia and the Withdrawal of the Western Group of Forces" (Macmillan, 1996).

Praeger Publishers in Connecticut, with which Mr. Cox had a contract, received earlier this year a nearly complete manuscript for his new work, "Close Protection: The Politics of Guarding Russia's Rulers." The book, written for an academic audience, likely will come out late next year, said his editor, Heather Staines.

Mr. Cox was born in Aurora, Ill., but grew up in nearby Naperville. In 1978, he received a bachelor's degree from Cornell College in Iowa. He received a master's degree in international relations from Northern Illinois University in 1985.

Mr. Cox is survived by his mother, Esther, of Naperville, Ill.; two brothers and a sister.