Sen. Chuck Grassley (R-Iowa) said on Thursday that the unilateral public release by Sen. Dianne Feinstein (D-Calif.) of testimony from Fusion GPS founder Glenn Simpson eliminated any chance of White House aide Jared Kushner voluntarily testifying before the Senate Judiciary Committee, which Grassley chairs. Grassley’s remarks came during a hearing to consider several judicial nominations.

Simpson, who founded the Democrat-linked political opposition research firm that commissioned and paid for the infamous Steele dossier, testified before the committee last August. In a move that took Grassley and his colleagues by surprise, Feinstein, the top Democrat on the committee, unilaterally released a redacted transcript of Simpson’s interview with the Judiciary committee. Grassley said Feinstein’s gambit, which suggested the committee could not be trusted to honor confidentiality agreements it promised in exchange for voluntary testimony, had the effect of spooking witnesses who had not yet been interviewed by the committee.

“I had hoped to speak with all the witnesses surrounding the Trump Tower meeting before releasing any of those interview transcripts,” Grassley said. “But the Ranking Member unilaterally released the transcript of Fusion GPS founder Glenn Simpson. That has spooked other potential witnesses.”

“As a result, it looks like our chances of getting a voluntary interview with Mr. Kushner have been shot,” he added.

Voluntary testimony is important because it precludes the possibility of witnesses pleading their Fifth Amendment rights against being compelled to provide testimony that incriminates themselves in potential criminal activity. As a result, congressional investigators often prefer voluntary interviews under the belief that some information is better than zero information. Once a witness who has been compelled to appear before a court or investigative body pleads the Fifth, the chances of investigators learning important new facts from that person are virtually non-existent.

Grassley said he hopes to get access to a transcript of the testimony Kushner already provided before the Senate Intelligence Committee, since Feinstein serves on that committee as well. A similar arrangement was negotiated for testimony provided by Paul Manafort.

In his statement to the committee, Grassley noted that without Kushner’s testimony, the Judiciary Committee’s interviews with participants in the 2016 Trump Tower meeting were concluded. He then called for the full public release of all of the testimony provided to the committee during the course of its investigation.

“I believe this Committee’s interviews of the witnesses surrounding the Trump Tower meeting are complete,” Grassley said. “That section of our investigation is done. So, now it’s time to start officially releasing the transcripts of all witness interviews we have done related to that meeting.”

“Let’s get them out there for everyone to see,” he concluded.

Grassley noted that if Feinstein were to object to the full public release of the interview transcripts, a committee vote to release them would likely be necessary.