A Russian man that offered to sell damaging information on Hillary Clinton to the campaign of then-candidate Donald Trump revealed in earlier court documents that he had been a long-time FBI informant. The man, Henry Greenberg, offered to sell the unspecified information for $2 million in late May, 2016, but the Trump campaign associate refused. Greenberg, who also used the name Oknyansky, filed two dozen documents with a federal court in 2015, showing an FBI agent repeatedly brokered his entry into the United States on a special visa for people assisting law enforcement. “I cooperated with the FBI for 17...