Washington (CNN) The Justice Department's internal watchdog Thursday repeatedly criticized former FBI Director James Comey for his actions during the 2016 presidential campaign.

Comey oversaw the investigation into Democratic presidential nominee Hillary Clinton and her handling of classified emails on her private server while she was secretary of state, but Comey's actions have come under scrutiny.

The DOJ inspector general panned many of his key decisions, though he did agree with the recommendation not to charge Clinton.

Here's a breakdown of what the IG's 500-page report found:

Publicly announcing his Clinton recommendation

COMEY ACTION: Comey announced in July 2016 that he was not recommending charges against Clinton. This move was unorthodox because FBI directors don't usually talk about prominent cases with the level of specificity that Comey did, especially if charges are not expected.

REPORT CONCLUSIONS: "While we found no evidence that Comey's statement was the result of bias or an effort to influence the election, we did not find his justifications for issuing the statement to be reasonable or persuasive."

Not telling his bosses about the recommendation

COMEY ACTION: Before that news conference, Comey decided he would not inform his bosses at the Justice Department. He also instructed his FBI colleagues not to tell their counterparts at the Justice Department.

REPORT CONCLUSION: "We found that it was extraordinary and insubordinate for Comey to do so, and we found none of his reasons to be a persuasive basis for deviating from well-established Department policies in a way intentionally designed to avoid supervision by Department leadership over his action."

Not bringing criminal charges against Clinton

COMEY ACTION: Comey recommended no charges against Clinton, saying: "Although there is evidence of potential violations of the statutes regarding the handling of classified information, our judgment is that no reasonable prosecutor would bring such a case."

REPORT CONCLUSION: "The Midyear team concluded that such proof (of crimes by Clinton) was lacking. We found that this interpretation of (the law) was consistent with the Department's historical approach in prior cases under different leadership, including in the 2008 decision not to prosecute former Attorney General Alberto Gonzales for mishandling classified documents."

Telling Congress about new Clinton emails

COMEY ACTION: In fall 2016, FBI investigators found new Clinton emails on the laptop of disgraced former Rep. Anthony Weiner. Comey sent a letter in late October 2016 to members of Congress announcing that his investigators were examining the new emails, essentially re-opening the probe.

REPORT CONCLUSION: "We found no evidence that Comey's decision to send the October 28 letter was influenced by political preferences ... we found that in making this decision, Comey engaged in ad hoc decisionmaking based on his personal views even if it meant rejecting longstanding Department policy or practice."

Keeping the Russia investigation secret

COMEY ACTION: Comey spoke publicly on several occasions during the 2016 presidential campaign about the Clinton email investigation. But he never revealed to the American public, until after the election, that the FBI was examining potential collusion between the Trump campaign and Russia.

REPORT CONCLUSION: "We found unpersuasive Comey's explanation as to why transparency was more important than Department policy and practice with regard to the reactivated Midyear investigation while, by contrast, Department policy and practice were more important to follow with regard to the Clinton Foundation and Russia investigations.