Sen. Sheldon Whitehouse sharply criticized congressional oversight of the Trump administration on Thursday, calling the Senate Judiciary Committee’s probe less than thorough and questioning whether House members may have engaged in obstruction of justice.

“We have not done nothing in the Senate Judiciary Committee, and I appreciate that,” the Rhode Island Democrat said in a measured tone during a committee meeting. “But we are a long way from the Senate Judiciary Committee having real answers on important questions that go to the heart of our committee’s oversight responsibilities.”

Whitehouse proposed that the panel start with a bipartisan effort to answer just three questions that he said remain “unanswered or unasked.” His comments come in the wake of President Donald Trump’s former personal lawyer pleading guilty to campaign finance charges that implicate the president’s involvement.

First, the committee has not asked for an accounting of Trump businesses’ dealings with and obligations to Russian interests, Whitehouse said.

Second, the committee has not pursued whether Donald Trump Jr. gave false testimony to the committee in September 2017 about a meeting with Russian lawyer Natalia Veselnitskaya at Trump Tower in June 2016.

Third, it has not pursued evidence behind questionable assertions of executive privilege before congressional committees.

“Other committee colleagues may be able to add to this list,” Whitehouse said. “But just from this list it is hard to say we have been thorough.”

The committee could hire an outside law firm or trusted lawyer to answer those three questions, backed by the committee’s subpoena power. Chairman Charles E. Grassley responded that he would take the request under consideration.

Sen. Dianne Feinstein of California, the top Democrat on the committee, told Grassley she would be happy to work with him on this because “I don’t think the situation is going to go away.”

Whitehouse, a former attorney general of the Ocean State, saved his most critical comments for House lawmakers. He said the Senate Judiciary Committee is under pressure “to be thorough and fearless in pursuing our oversight responsibilities” because of a House probe that has “utterly failed to clear the air” regarding the possibility lawmakers have been in communication with Trump or his representatives “in their so-called investigation.”

“It is impossible to rely credibly on the House investigators,” Whitehouse said. “And in my view, it is an open question whether they themselves may have engaged in obstruction of justice.”