Congressional leaders investigating the FBI’s suspiciously inept investigation of ex-Secretary of State Hillary Clinton’s emails are turning their attention to FBI chief James Comey’s truthfulness. Did he mislead them? Did he perjure himself?

Two days after clearing Clinton of criminal wrongdoing, Comey went to Capitol Hill and explained his reasons for coming to that stunning conclusion. Testifying under oath, he claimed to be an open book: “I think transparency matters tremendously.”

But he not only held back critical details about his investigation, he repeatedly misrepresented his actions and findings.

In his July 7 testimony, Comey assured Congress that he examined all the evidence of Clinton’s lawyers and aides deleting her emails, and concluded they weren’t trying to hide anything. “We did not find evidence to indicate that they did the erasure to conceal things of any sort,” he swore. “We didn’t find evidence of evil intent to obstruct justice there.”

“In his statements before Congress, Director Comey repeatedly assured us that the FBI investigated whether charges of obstruction of justice and intentional destruction of records were merited,” the chairmen of three House committees and a Senate committee complained last week in a letter to Attorney General Loretta Lynch. “The facts of this investigation call those assertions into question.”

Congress has now obtained letters detailing unprecedented immunity agreements and side deals with multiple witnesses in the case — including one in which Comey agreed to prevent his investigators from reviewing any emails from Clinton chief of staff Cheryl Mills to Clinton’s server administrator Paul Combetta generated in late 2014 and early 2015. The off-limits correspondence, the chairmen point out, could reveal information “directing the destruction or concealment of federal records.”

Astonishingly, before Comey agreed to the June side deal with Mills’ attorney, he “already knew of the conference calls between Secretary Clinton’s attorneys and Mr. Combetta, his use of BleachBit, and the resulting deletions, further casting doubt on why the FBI would enter into such a limited evidentiary scope of review.”

In other words, Comey never really investigated Clinton and her aides for obstruction of justice, as he claimed. Lacking access to key evidence, he couldn’t have explored the possibility, though the circumstances were beyond suspicious.

“The sequence of events leading up to the destruction of Secretary Clinton’s emails — the conference call, the work ticket, the use of BleachBit, and [Combetta’s] subsequent refusal to discuss the conference call with the FBI — raises questions about whether Secretary Clinton, acting through her attorneys [including Mills], instructed [Combetta] to destroy records relevant to the then-ongoing congressional investigations,” noted House Oversight Committee Chair­man Jason Chaffetz.

In his July testimony, Comey said it was unclear if anyone had helped Clinton’s lawyers delete emails — yet he had to have known that Combetta, in his final interview under his immunity deal, had admitted destroying evidence under subpoena.

Comey also swore his team asked Clinton if she knew her lawyers had wiped clean the devices containing her email archives, when it seems clear from the summary of her interview that agents did not ask her that question.

“Did you ask that question?” Rep. Jim Jordan (R-Ohio) asked.

“Yes,” Comey replied.

In 4½ hours of testimony, Comey never once mentioned that he’d agreed to give Mills, Combetta and three other key subjects of his investigation immunity from prosecution. Also belying his pronouncements of “transparency,” he failed to reveal the unusual side deals that severely limited the scope of his probe.

Congressional investigators only learned about the deals weeks later, and still have not obtained all of the documents.

Lynch and Comey have redacted parts of the side-deal letters, including the names of all Justice Department and FBI personnel. They have also restricted access to the letters to certain members of Congress, while prohibiting even those members from removing them from the secure viewing room where they are kept. They’re also barred from taking notes.

“These onerous restrictions are not consistent with the high degree of transparency you and director Comey promised to Congress,” the chairmen complained.

Though Comey has turned over some 250 pages of investigative-case summaries and witness-interview summaries known as FBI 302s, he’s still withholding summaries of interviews with some 30 other witnesses.

It’s more evidence that Comey hasn’t been straight with the public about this probe, and raises serious questions about his integrity.

Congress must treat Comey as a hostile witness and investigate the investigator.

Paul Sperry, formerly DC bureau chief for Investor’s Business Daily, is the author of “Infiltration.”