Senate Judiciary Committee Chairman Chuck Grassley, R-Iowa, this week pushed the FBI to turn over all documents relating to Peter Strzok, the official who was removed from special counsel Robert Mueller’s team due to political bias.

Grassley asked Strzok in October for an interview, which never happened, so Grassley asked FBI Director Christopher Wray in a Tuesday letter for answers. Grassley is one of a handful of Republican lawmakers who had questioned the FBI and Department of Justice months ago about Strzok, and is renewing his effort after reports that Strzok exchanged "politically charged texts disparaging President Trump and supporting Hillary Clinton."

Strzok was working on the investigation of Clinton's private email server at the time, but Grassley said his bias could have influenced that case, as well as the special counsel's investigation of members of President Trump's team, such as former national security adviser Michael Flynn.

"The communications between members of the Clinton email investigation team raise questions about the integrity of that investigation, and about the objectivity of Mr. Strzok's work for the Special Counsel and in the FBI's investigation of Mr. Flynn," Grassley wrote in his letter.

Grassley asked Wray for all communications involving Strzok during his work in those investigations, including any communications involving the FBI's decision to change the finding that Clinton was "extremely careless" instead of "grossly negligent" in handling emails. That change, which Strzok was reportedly behind, helped Clinton evade possible criminal charges.

Grassley demanded that information by Monday, Dec. 11.