Grassley sent a letter to Secretary of State John Kerry Friday asking for the letters of Bryan Pagliano. Grassley, who chairs the Senate Judiciary Committee, said Pagliano's emails were the committee's "highest priority request."
"Given that the Committee is unable to obtain his testimony at this time, I am seeking copies of his official State Department emails relevant to the Committee's inquiry before proceeding to consider whether it might be appropriate to grant him immunity and compel his testimony," Grassley wrote.
Grassley's letter says State Department officials could not find a backup file of Pagliano's emails, and instead are searching for emails of those who corresponded with Pagliano of which there are a "limited number."
Earlier this week, Grassley asked FBI director James Comey whether the FBI had Pagliano's computer. Comey did not comment due to the ongoing investigation. Pagliano has previously declined to testify, invoking his fifth amendment rights.
Grassley's letter said the committee will not consider its request fulfilled until the State Department explains why there is no backup of Pagliano's emails. He also called for the department to provide "expert witnesses" to explain why the department did not keep Pagliano's emails.