Sen. Chuck Grassley (R-Iowa) announced that he will “place holds” on approving Trump administration nominees until he receives a satisfactory explanation about the firings of two federal watchdogs: Intelligence Community Inspector General Michael Atkinson and State Department Inspector General Steve Linick.

Atkinson was fired after alerting Congress to the whistleblower complaint pertaining to President Donald Trump‘s communications with Ukraine, which ultimately led to his impeachment in December. Linick was fired on May 15 at the behest of Secretary of State Mike Pompeo, whom Linick was reportedly investigating.

In two follow-up tweets on Friday, Grassley continued to put pressure on Trump but called out former Secretary of State Hillary Clinton for never having an inspector general.

“Canning a watchdog without good reason is bad… Never even hiring one is outrageous,” he wrote. “Where were the complaints when Obamas state IG seat sat empty for FOUR YEARS??”