After Paul Manafort's Virginia home was raided by the FBI on July 26, Special Counsel Robert Mueller's prosecutors told him that they plan on indicting him, two people with knowledge of the situation told The New York Times.
Federal agents picked a lock to gain access to Manafort's house on July 26, and gathered binders and documents and copied computer files in their search for evidence that he has secret offshore bank accounts, the Times reports. In order to get a federal judge to grant permission to enter without knocking, Mueller's team had to argue that they believed Manafort was likely to destroy evidence; this happened after they had to show probable cause there was evidence of a crime at the house, the Times says.
The raid came the day after Manafort was interviewed by staffers of the Senate Intelligence Committee, and the same day he was supposed to talk to the Senate Judiciary Committee; that meeting was canceled. Manafort is being investigated for possible violations of tax law and money-laundering prohibitions. You can read more about Mueller's goals and "shock-and-awe" tactics at The New York Times.