The puzzle pieces were strewn about the board late last week, several small fragments waiting to be put together. There were signs aplenty something was coming in the congressional and federal probes into Russia’s 2016 election meddling, but in isolation, each piece failed to reveal much.

A relatively quiet day at the White House was upended Friday evening by a CNN report that Justice Department special counsel Robert S. Mueller III is poised to reveal formal charges against individuals who once had ties to or remain close to President Donald Trump. Other major media outlets matched the report, which came after several brow-furrowing developments that suggested increased activity in the federal inquiry.

The signs began to emerge Thursday afternoon. Richard M. Burr, the North Carolina Republican leading the Senate’s Russia probe, had a light but noteworthy encounter with reporters.

As members finished their work week, Burr walked in the Senate basement toward the subway tunnel. Perhaps surprised that he was unmolested by journalists who have been eager to buttonhole him over the last several months about the investigation, he held up his hands and made a face.

“Aren’t you going to ask questions?” he said in a jocular tone, addressing a small group of reporters who lingered. When one reporter replied that he never answered, Burr shrugged and said, “Yeah, but you can still ask,” acknowledging his recent tight-lipped approach. The group laughed, and Burr made his way to the train heading to the Dirksen and Hart Senate office buildings, seemingly in a breezier mood than he had displayed of late.