Senator Chuck Grassley.

Iowa Senator Chuck Grassley says Monday’s release of a U.S. Justice Department inspector general’s report on allegations of wrongdoing by the FBI confirms what he’s long suspected.

“The FBI abused its power when it spied on Trump campaign officials in 2016,” Grassley says. The 434-page report, according to Grassley, makes it clear the bureau conducted an illegal investigation that was instigated by political bias in probing allegations of Russian interference in the U.S. presidential election.

“In doing so, it sidelined the constitutional rights of an American citizen based on rumors, omissions and in at least one instance, a whopper of a lie,” he says. Anyone who values fundamental civil liberties should be “disgusted and terrified” by what the report uncovered, according to Grassley.

“The inspector general found at least 17 errors or omissions in the FBI’s application to eavesdrop on the Trump campaign advisor,” he says. Grassley, a Republican who serves on the Senate Judiciary Committee, says the inspector general is conducting an audit of FISA, the Foreign Intelligence Surveillance Act program.

“Tomorrow, the inspector general will testify before the Judiciary Committee about the report. I will be there,” Grassley says. “It’s critical that we prevent this abuse of civil liberties in the future.” Grassley says the report makes it seem as if J-Edgar Hoover was still in charge of the FBI, as he says Hoover was notorious during his tenure between the 1920s and ’60s for spying and “violating people’s civil liberties.”