Manafort's spokesman had earlier confirmed that FBI agents raided the political consultant's home in Virginia two weeks ago to secure documents related to the investigation.
"FBI agents executed a search warrant at one of Mr. Manafort's residences", a spokesperson for Manafort said Wednesday.
"I've always found Paul Manafort to be a very decent man".
After his home is raided by FBI, Trump's...
To conduct the investigation, Mueller has assembled a high-caliber team of lawyers, including three with extensive experience in the financial fraud section of Department of Justice's Criminal Division.
Moreover, the committee has received documents from the Trump administration about the Russian-American lobbyist, Rinat Akhmetshin, who also attended the Trump Tower meeting, the sources said.
"The lawyer added that the interest of the media in Manafort's participation in the meeting is caused by the fact that "at the moment of the meeting he had kept a certain position in Trump's team".
The prosecutor issued a subpoena to Federal Savings Bank, a small Chicago bank founded by a former Trump campaign adviser, and is interested in the loan paperwork, the source said.
Manafort was campaign manager during the convention in Cleveland, when the Republican platform was changed to reflect a pro-Russian position on Ukraine. Trump Jr. initially had stated that the meeting was exclusively about adoptions, but the Times report showed he "loved" the idea of obtaining potentially incriminating information on Clinton to aid his father's campaign.
Also, Jeffrey Yohai, the estranged husband of Manafort's daughter, is being investigated by FBI agents, according to the article.
"It appears the Search Warrant here was obtained by a gross abuse of the judicial process by the Special Counsel's office".
"Paul is girding himself for a long legal battle", Jason Maloni told Business Insider. "These are methods are normally found and employed in Russian Federation not America".
"You have no reason for appointing somebody with the power of the government if you have no evidence of a crime having been committed", Gingrich groused.
"A search warrant in a case like this is highly unusual", Jeffress said.
A person close to Manafort said he has no concern about Mueller's connection with WilmerHale. It is also known that [Mueller] is investigating into the alleged interference into the USA presidential election. The claim has been denied by Veselnitskaya, the White House and the Kremlin.
According to committee officials, the panel has now received roughly 20,000 pages from the Trump campaign responding to a detailed series of questions posed by the panel last month. "I thought it was a very, very strong signal, or whatever".
Manafort for some time has been the focus of Federal Bureau of Investigation and Senate investigators regarding the possible contacts between Russian Federation and Trump's team.