That's what the government that handed Assange over, and which is now cooperating with his persecutors, claimed - without any evidence, of course. That government also happens to be pursuing friendly relations with the United States, and also just happened to receive a large IMF loan, not that those things could possibly be related to the decision to revoke Assange's asylum.

Political asylum is not normally revoked because someone is a bad house guest, and one former embassy employee has gone on the record stating that the new Ecuadorian government did its best to make Assange's life in the embassy living hell, and that he was actually a courteous guest. It is in the interest of the Ecuadorian government to defame Assange and to make excuses for their sudden cooperation with American authorities.