WASHINGTON — The Justice Department should require high-level approval before the FBI opens an investigation into a major political campaign, the department’s inspector general was prepared to testify Wednesday as he briefed senators on his report into the probe of the Trump campaign in 2016.

Inspector General Michael Horowitz’s prepared testimony said that he found no evidence the FBI sought to insert informants into the Trump campaign. But, the report he released Monday says, the FBI did use “confidential human sources (CHS’s),” to speak to and record members of the Trump campaign, including George Papadopoulos, Carter Page and an unnamed senior official.

“There is no applicable Department or FBI policy requiring the FBI to notify Department officials of a decision to task CHS’s to consensually monitor conversations with members of a presidential campaign,” Horowitz was to testify to the Senate Judiciary Committee.

Horowitz’s prepared testimony also expresses deep misgivings about the FBI’s errors and omissions in its requests for judicial approval to conduct surveillance on Page.

“We are deeply concerned that so many basic and fundamental errors were made by three separate, hand-picked investigative teams; on one of the most sensitive FBI investigations; after the matter had been briefed to the highest levels within the FBI,” Horowitz’s prepared testimony said.

In his opening statement at Wednesday’s hearing, Judiciary Committee Chairman Sen. Lindsay Graham, R-S.C., painted the FBI’s conduct in dire terms, describing what happened as “a massive conspiracy over time to defraud the FISA court, to illegally surveil an American citizen” and to investigate a sitting president.