WASHINGTON — The gun-toting Russian security agents who burst into Edmond Pope's hotel room in Moscow last April videotaped his arrest on suspicion of espionage, catching the retired U.S. Navy captain in slack-jawed astonishment. Pope, 54, a businessman who scoured Russia for promising technologies, is said to have remained baffled for the eight months he spent in the 18th-century Lefortovo Prison. Charged with stealing state secrets, he was tried behind closed doors this fall and sentenced to 20 years in prison. Pope was pardoned by President Vladimir Putin on humanitarian grounds Dec. 14 and is now back at home in State College, Pennsylvania. Why the Federal Security Service, or FSB, arrested Pope is a tangled affair still shrouded in secrecy. A former Navy intelligence officer, he was operating in a dangerous gray area when he sought to buy Russian technology that could be useful to the Pentagon. But sources knowledgeable about U.S.