WaPo reporting today that on July 26th, the FBI raided Manafort's home and took documents believed to be related to various investigations into his activity:

FBI agents raided the Alexandria home of President Trump’s former campaign chairman late last month, using a search warrant to seize documents and other materials, according to people familiar with the special counsel investigation into Russian meddling in the 2016 election.

The search warrant was wide-ranging and FBI agents working with special counsel Robert S. Mueller III departed the home with various records.

The raid came as Manafort has been voluntarily producing documents to congressional committees investigating Russia’s interference in the 2016 presidential election. The search warrant indicates investigators may have argued to a federal judge they had reason to believe Manafort could not be trusted to turn over all records in response to a grand jury subpoena.

It could also have been intended to send a message to President Trump’s former campaign chairman that he should not expect gentle treatment or legal courtesies from Mueller’s team.