Agents from America's Federal Bureau of Investigation (FBI) have reportedly seized diaries belonging to actress Anne Hathaway in relation to her ex-boyfriend's fraud case.

The Devil Wears Prada star is said to have broken up with Italian Raffaello Follieri last month, shortly before he was arrested on suspicion of unscrupulous business dealings.

Follieri has been charged with a dozen counts of federal wire fraud conspiracy and money laundering and will remain in jail until he can post $21 million bail.

Now FBI agents have reportedly raided Follieri's luxury New York apartment - in Donald Trump's Trump Tower - seizing a variety of his personal possessions, including Hathaway's private diaries, according to the New York Daily News.

Officers are also reported to have taken an assortment of documents, watches and personal photos of Follieri and Hathaway.