Robert Mueller

A lot of people are counting on special counsel Robert Mueller.

Federal prosecutors have lots of ways to intensify pressure on the people they're investigating, from early morning FBI raids to leaning on relatives of those under government scrutiny.

But even by those measures, the special counsel investigating Russian interference in last year's presidential election is moving with unusual speed and assertiveness, according to half a dozen legal experts following the probe.

Updated at 10:29 a.m.

The Senate is long gone. The House? Splitsville. The president is at his golf club in New Jersey. Only the hardiest swamp creatures continue to scuttle in and out of the half-empty offices of late-August Washington, D.C.

Justice Department special counsel Robert Mueller and his team, however, haven't gone anywhere.

Updated at 8:30 p.m. ET

Special counsel Robert Mueller is using a grand jury in Washington, D.C., in connection with his investigation into Russian efforts to influence the 2016 presidential election and into possible collusion between Russia and top aides to the Trump campaign, a source with knowledge of the investigation confirms to NPR's Peter Overby. The source did not want to be identified because of the sensitivity of the matter.

Robert Mueller has made no public comment since he was named to lead the Department of Justice investigation into Russian interference in last year's election.

Instead, he has let his actions do the talking. The former FBI director and decorated U.S. Marine has submitted a budget and quietly hired an all-star team that includes 15 Justice Department prosecutors. And, a spokesman for Mueller said, he's not done bringing on new lawyers.

Updated at 1:15 p.m. ET

In what has ignited another firestorm of debate in polarized Washington, a longtime friend of President Trump said Monday night that Trump is "weighing" whether to dismiss Robert Mueller, the Justice Department special counsel investigating possible ties between the Russian government and the Trump campaign.

Updated at 5:06 p.m. ET

Former FBI Director James Comey told the Senate Intelligence Committee that he believed he was fired by President Trump over the growing Russia investigation and that other arguments by the White House were "lies, plain and simple."

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Next we're going to hear from California Democrat Eric Swalwell. He serves on the House Permanent Select Committee on Intelligence and also the House judiciary committee. Welcome to the program.

ERIC SWALWELL: Thanks for having me back.

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Updated at 9:15 p.m. ET

The Justice Department is appointing former FBI Director Robert Mueller as a special counsel to oversee the growing probe into Russian meddling in the 2016 election and possible ties to associates of President Trump.

"In my capacity as acting Attorney General, I determined that it is in the public interest for me to exercise my authority and appoint a Special Counsel to assume responsibility for this matter," Deputy Attorney General Rod Rosenstein said in a statement.