“There should be no improper interference with F.B.I. investigations to favor any elected official or candidate of either party,” Mr. Grassley said in a letter to Ms. Feinstein. “The committee has an obligation to pursue all evidence of such misconduct.”
For its part, the House Judiciary Committee has so far steered clear of the Russia investigation.
Senate Intelligence Committee: Keeping its eyes on Russia.
The top Republican and the top Democrat on the Senate Intelligence Committee told CNN on Thursday that they would largely leave the investigation into obstruction of justice, a criminal matter, to Robert S. Mueller III, the special counsel overseeing the Trump-Russia inquiry, with whom they met on Wednesday.
The committee will continue to focus on its investigation into Russian interference, including potential collusion between Mr. Trump’s associates and the Russians.
Next week, the committee will hold a public hearing with intelligence experts and election officials about Russian interference in the 2016 election, as well as how to thwart future meddling.
It was a busy week for the committee, though most of that activity took place behind closed doors. In addition to hearing from Attorney General Jeff Sessions, the committee’s members and staff privately questioned Adm. Michael S. Rogers, the head of the National Security Agency; Dan Coats, the director of national intelligence; and Jeh Johnson, the former secretary of Homeland Security.
Admiral Rogers and Mr. Coats testified as a follow-up to their recent public appearance, when committee members pressed them on whether Mr. Trump had asked them to pressure Mr. Comey to drop the investigation into Michael T. Flynn, the president’s former national security adviser.
And the House Intelligence Committee? Stay tuned.
Will they or won’t they?
Representative Adam B. Schiff of California, the top Democrat on the House Intelligence Committee, said in an interview on Thursday that he was pushing for the panel to include obstruction of justice in its investigation. It is unclear whether Representative K. Michael Conaway of Texas, the Republican leading the inquiry, agrees.
The House panel will hold a public hearing with Mr. Johnson on Wednesday, signaling that it is staying focused specifically on the question of Russian interference. Mr. Johnson was homeland security secretary last year when hackers carried out attacks on the Democratic National Committee and some state election databases.
In the months since Mr. Comey declared before the House committee that the F.B.I. was examining whether Mr. Trump’s associates worked with Russians to interfere in the election, the Senate Intelligence Committee has largely attracted the spotlight with its closely watched public hearings as the House panel has kept a lower profile.
Last month the House investigation issued subpoenas to Mr. Flynn and Michael D. Cohen, one of Mr. Trump’s personal attorneys, as well as their businesses.