Sen. Dianne Feinstein’s (D-Calif.) decision to release a 300-page transcribed interview with Fusion GPS co-founder Glenn Simpson was described as “confounding” by Senate Judiciary Committee Chairman Chuck Grassley (R-Iowa) on Tuesday.

Grassley was not consulted before Feinstein, the Judiciary Committee’s top Democrat, took it upon herself to release the transcript. He says her actions have compromised the Judiciary Committee’s ability to conduct its investigation into Russian meddling in the 2016 election.

Grassley had opposed the release of the transcript, while Fusion GPS had demanded that it be released.

“Her action undermines the integrity of the committee’s oversight work and jeopardizes its ability to secure candid voluntary testimony relating to the independent recollections of future witnesses,” said a spokesman for Grassley.

Grassley’s spokesman pointed out the fact that no other congressional panel had released transcripts of private interviews related to the Russia investigations, and further suggested that Feinstein’s decision may discourage potential witnesses from testifying before the Judiciary Committee.

The private research firm commissioned the 2016 dossier, which includes salacious and unverified allegations about President Trump. The document was compiled by Christopher Steele, a former British intelligence official, who was hired by Fusion GPS.

Grassley and Sen. Lindsey Graham (R-S.C.) have referred Steele to the Justice Department for criminal investigation.