WASHINGTON Former Trump campaign chairman Paul Manafort and onetime business associate Rick Gates were indicted by a federal grand jury on charges of conspiracy and money laundering in connection with an intensifying investigation into Russian meddling in the 2016 presidential election.

Manafort left his Virginia condo and, with his attorney, walked into the FBI field office in Washington early Monday. A 12-count federal grand jury indictment unsealed shortly after his surrender includes charges of conspiracy against the U.S., conspiracy to launder money, failure to file foreign bank reports and false statements.

Manafort and Gates both pleaded not guilty to the charges in federal court.

Separately, a former Trump campaign foreign policy adviser has pleaded guilty to lying to FBI agents about Russian dirt he was offered on Hillary Clinton, according to a plea deal prosecutors unsealed Monday. George Papadopoulos, 30, pleaded guilty on Oct. 5 and has been cooperating in the Russia probe.

The charges are the first in the probe led by the office of special counsel Robert Mueller , a former FBI director. Mondays arrests come three days after news broke that a federal grand jury in Washington had filed charges stemming from Muellers investigation.

Manafort and Gates generated tens of millions of dollars in income as a result of their Ukraine work, the indictment says. In order to hide Ukraine payments from United States authorities, from approximately 2006 through at least 2016, Manafort and Gates laundered the money through scores of United States and foreign corporations, partnerships, and bank accounts.

Failing to pay taxes allowed Manafort a lavish lifestyle in the United States, according to the indictment, which alleges he spent millions of dollars on luxury goods and services for himself and his extended family through payments wired from offshore nominee accounts to United States vendors.

Manafort laundered more than $18 million, which he used to buy property, goods and services in the U.S., the indictment alleges. Hes accused of spending $849,215 at one clothing store, $520,440 at another clothing store, about $934,000 at an antique rug store, $62,750 for a Mercedes Benz, and $47,000 for a Range Rover.

Reports have suggested federal investigators could use criminal charges as way to pressure those arrested into providing more information about alleged collusion between President Donald Trump s campaign and the Kremlin to influence the election. The indictment charging Manafort and Gates makes no mention of Trump or the election.