Senate Judiciary Chairman Chuck Grassley said the FBI is blocking release of key portions of a memo he wrote calling for a criminal investigation of Christopher Steele, the former British spy who compiled a dossier of unverified allegations on Donald Trump.

“Seeking transparency and cooperation should not be this challenging,” Grassley said in a statement after posting a heavily redacted version of the criminal referral that he and GOP Senator Lindsey Graham of South Carolina sent to the Justice Department last month. “The government should not be blotting out information that it admits isn’t secret.”

Grassley, an Iowa Republican, has been pursuing questions about the FBI’s reliance on Steele separately from House Intelligence Chairman Devin Nunes, who last week released a disputed memo alleging bias in the early stages of the bureau’s continuing investigation into Russian meddling in the 2016 presidential campaign and whether anyone close to Trump colluded in it.

Democrats have dismissed the memo as inaccurate and misleading and are pushing for release of their own document challenging the Republican account. The Intelligence panel is scheduled to meet Monday at 5 p.m. Washington time to vote on the possible release of the Democratic response.

Grassley and Graham asked the Justice Department to investigate whether Steele made false statements to federal investigators. In the newly released memo, the pair wrote that they sent the criminal referral because there’s evidence that Steele — whose opposition research was funded largely by Trump rival Hillary Clinton and the Democrats — either lied to the FBI or to a British court, or that classified documents reviewed by the committee are false.

Grassley asked the FBI to approve a declassified version of his Steele referral by Tuesday.

Among the portions of the Grassley letter that remain redacted are verbatim quotes from applications to a court for surveillance of former Trump adviser Carter Page as well as the government’s description of Steele’s statements to the FBI about his contacts with the media.

Blacked out in the redacted letter is a section headed by the sentence “there is substantial evidence suggesting that Mr. Steele materially misled the FBI about a key aspect of his dossier efforts, one which bears on his credibility.”

A section on a second memo by Steele quotes it as saying he received the report from the State Department, which in turn got it from a foreign source who was in touch with “a friend of the Clintons.”

“It is troubling enough that the Clinton Campaign funded Mr. Steele’s work, but that these Clinton associates were contemporaneously feeding Mr. Steele allegations raises additional concerns about his credibility,” Grassley and Graham wrote in their criminal referral.