Democratic Rep. Adam Schiff said President Trump should have to testify under oath as part of special counsel Robert Mueller’s Russia investigation.

Schiff, the chairman of the House Intelligence Committee, was asked about the possibility of Mueller concluding his investigation before bringing the president before a grand jury in light of conflicting comments from Trump and his former longtime lawyer Michael Cohen.

“I do think ultimately it’s a mistake, because probably the best way to get the truth would be to put the president under oath. Because, as he’s made plain in the past, he feels it’s perfectly fine to lie to the public. After all, he has said, ‘It’s not like I’m talking before a magistrate.’ Well, maybe he should talk before a magistrate,” Schiff told NBC’s “Meet the Press.”

Schiff said Mueller, who’s investigating whether Trump or his campaign officials colluded with the Russians during the 2016 election, shouldn’t rely on written answers from the president’s legal team.

“When you get written answers from a witness, it’s really the lawyers’ answers as much as the client’s answer. And here you need to be able to ask follow-up questions in real time,” he said.

Schiff also said Mueller and his investigators are working on time constraints to finish up their probe and Attorney General William Barr who “would likely oppose” a subpoena of Trump.

Trump’s personal lawyer Rudy Giuliani has said he wouldn’t let the president be interviewed by Mueller because the special counsel would set a perjury trap.