In 1986, he was briefly detained by Soviet security services on espionage charges, sparking a diplomatic crisis.

His grandfather, general Yuri Danilov, was a chief of operations of Russian Imperial Army general-headquarters during World War I.

On September 7, 1986, Daniloff was notified of a charge and had a proceeding scheduled for 2 pm at Lefortovo Prison in Moscow.

The Soviets expelled ten U.S. diplomats and withdrew all 260 of the Russian support staff working for the U.S. embassy in Moscow.

[1] Daniloff later contended in his autobiography, Two Lives, One Russia, that he had never held classified documents, and that the KGB had created false information.