The special counsel, Robert S. Mueller III, announced charges on Monday against three advisers to President Trump’s campaign and laid out the most explicit evidence to date that his campaign was eager to coordinate with the Russian government to damage his rival, Hillary Clinton.

The former campaign chairman, Paul Manafort, surrendered to the F.B.I. and pleaded not guilty on charges that he laundered millions of dollars through overseas shell companies — using the money to buy luxury cars, real estate, antique rugs and expensive clothes. Rick Gates, Mr. Manafort’s longtime associate as well as a campaign adviser, was also charged and turned himself in.

But information that could prove most politically damaging to Mr. Trump came an hour later, when Mr. Mueller announced that George Papadopoulos, a former foreign policy adviser to the Trump campaign, had pleaded guilty to lying to the F.B.I. and was cooperating with investigators. In court documents released on Monday, federal investigators said they suspected that Russian intelligence services had used intermediaries to contact Mr. Papadopoulos to gain influence with the campaign, offering “dirt” on Mrs. Clinton in April 2016 in the form of “thousands of emails.”