They posed as ordinary citizens, living daily, nondescript lives in communities from Arlington, Va., to Yonkers, N.Y. They were married couples with car payments, monthly rents, and telephone and medical bills. They bought computers, gave gifts and ate occasionally in restaurants. But there was more. The FBI says 10 people arrested up and down the East Coast on Sunday were part of a deep-cover, or sleeper network, of Russian intelligence agents operating inside the United States, where they sought to infiltrate "policy-making circles" in Washington, recruit government and business sources, and "search and develop" intelligence ties in the United States....