The bipartisan leaders of the Senate Judiciary Committee on Thursday released a request that the Trump campaign provide emails from campaign aides John Mashburn and Rick Dearborn.

Dearborn, a former chief of staff of then-Sen. Jeff Sessions, went on to lead the Trump transition team and served for about a year in the White House. Mashburn was the Trump campaign’s policy director, and is currently the White House’s Deputy Cabinet Secretary.

“We are writing today because we believe information obtained in a recent Committee interview warrants expanding those searches to two additional custodians who were not included in the original effort, John Mashburn and Rick Dearborn,” Judiciary Chairman Chuck Grassley (R-IA) and Ranking Member Dianne Feinstein (D-CA) wrote in a letter dated Tuesday. “Doing so will help ensure the Campaign’s production fully responds to the categories of documents sought in the Committee’s initial letter.”

The letter follows an earlier request for information sent by the senators to the Trump campaign last July, seeking emails from an assortment of other campaign officials.

“The Campaign has since provided over 28,000 pages of responsive documents, as well as letters detailing the 21 campaign custodians whose emails were searched and the more than 300 search terms used,” the senators noted in their Tuesday letter.

Dearborn’s name has appeared in reports about connections between the National Rifle Association, Russia and Trump associates. Dearborn was sent an email by an NRA activist in May 2016 with the subject line “Kremlin Connection,” seeking his and Sessions’ advice for setting up a meeting between Trump and Russian President Vladimir Putin.

Both Dearborn and Mashburn were also looped in on an effort to soften the GOP’s platform towards Russia with a Ukraine amendment, another campaign aide involved in the push told Business Insider.

Read the letter below: