Story highlights The Senate judiciary and intelligence committees are investigating Russian meddling

The judiciary panel met behind closed doors last week with Donald Trump Jr.

(CNN) Sen. Dianne Feinstein, the top Democrat on the Senate judiciary committee, said Monday she expects Donald Trump Jr. to return to the Senate at some point for a public hearing about his meeting last year with a Russian lawyer and others.

Trump Jr. was interviewed by Senate judiciary staff for close to four hours last week . Asked if she expected Trump Jr. to return, Feinstein told CNN, "I do -- come hell or high water."

Senate Judiciary Committee Chairman Chuck Grassley, who has amped up his committee's investigation of Russian interference in the US elections, was noncommittal on Tuesday when asked about the possibility of a public hearing.

"I'm going to talk to Sen. Feinstein about that, and make a decision after we talk to her," the Iowa Republican told CNN.

But interest in Trump Jr. from Hill investigators has remained steady since he released an email chain showing plans to meet with a Russian lawyer and others to obtain dirt on then-Democratic presidential candidate Hillary Clinton.