House Intelligence Committee Chairman Adam Schiff (D-CA) said on Sunday that one reason the whistleblower at the heart of the impeachment inquiry hasn’t been called by the House to testify is that President Donald Trump called the person a spy and threatened the whistleblower with the “death penalty.”

With the Intel Committee wrapping up its public impeachment hearings last week, Meet the Press anchor Chuck Todd asked Schiff on Sunday whether Schiff was going to be the House manager for impeachment.

“That’s up to the speaker,” Schiff answered, adding that he didn’t want to get ahead of the process as they haven’t filed articles of impeachment yet.

After Schiff said that the facts surrounding whether the president sought foreign interference in an election are not even being contested by Republicans, Todd then wondered aloud about Schiff’s position on having the whistleblower come forward.

“I know where you are with the whistleblower and the leaf that you don’t need to hear from the whistleblower anymore,” the NBC News host stated. “You did pledge that the Intelligence Committee would hear from the whistleblower in some form or another? Are you going to fulfill that pledge?”

Earlier this month, when the Republicans requested that the whistleblower be included among the impeachment witnesses called to testify, Schiff argued that the person’s testimony would be “redundant and unnecessary.” The whistleblower’s attorney further informed the GOP that his client would only answer questions in writing.

“We had a deep interest in having them testify,” Schiff told Todd. “Two things happened. One we were able to prove it with witnesses that had first-hand information and second the president and his allies effectively put that whistleblower’s life in danger.”

“The president said the whistleblower and others should be treated as a traitor and a spy and we ought to use the penalty and that’s the death penalty,” the California lawmaker continued. “So here’s the thing, Chuck, we don’t need the whistleblower’s second-hand evidence. It would only serve to endanger this person and gratify the president’s desire for retribution and that is not a good enough reason to bring in the whistleblower.”

In late September, after the whistleblower’s complaint was made public, the president told a group at a private event that the whistleblower was “close to a spy” and wanted to know who gave the information to the whistleblower.

“You know what we used to do in the old days when we were smart with spies and treason, right?” Trump added. “We used to handle it a little differently than we do now.”

Trump has also repeatedly asked if Schiff should be arrested for treason, claiming the chairman “illegally made up a FAKE & terrible statement” when he read a “parody” of Trump’s July 25 phone call with the Ukrainian president.