President Trump Donald John TrumpBiden on Trump's refusal to commit to peaceful transfer of power: 'What country are we in?' Romney: 'Unthinkable and unacceptable' to not commit to peaceful transition of power Two Louisville police officers shot amid Breonna Taylor grand jury protests MORE on Thursday sought credit for firing ex-FBI Director James Comey James Brien ComeyDemocrats fear Russia interference could spoil bid to retake Senate Book: FBI sex crimes investigator helped trigger October 2016 public probe of Clinton emails Trump jabs at FBI director over testimony on Russia, antifa MORE, even as the decision has attracted scrutiny from federal investigators.

"When will people start saying, 'thank you, Mr. President, for firing James Comey?'" Trump tweeted.

When will people start saying, “thank you, Mr. President, for firing James Comey?” — Donald J. Trump (@realDonaldTrump) June 7, 2018

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Trump delivered his latest criticism of his former FBI director as an upcoming inspector general report is expected to be critical of Comey's handling of the FBI's investigation into Hillary Clinton Hillary Diane Rodham ClintonDemocratic groups using Bloomberg money to launch M in Spanish language ads in Florida The Hill's Campaign Report: Presidential polls tighten weeks out from Election Day More than 50 Latino faith leaders endorse Biden MORE's use of a private email server while she was secretary of State.

Trump fired Comey in May 2017, prompting the appointment of special counsel Robert Mueller Robert (Bob) MuellerCNN's Toobin warns McCabe is in 'perilous condition' with emboldened Trump CNN anchor rips Trump over Stone while evoking Clinton-Lynch tarmac meeting The Hill's 12:30 Report: New Hampshire fallout MORE to lead the Justice Department's investigation into Russian interference in the 2016 presidential election, including any ties between Trump's campaign and Moscow.

The president's reasoning for cutting Comey loose has changed at times over the past year and has reportedly been a focal point of Mueller's investigation.

The White House initially said Trump fired Comey on the recommendation of Attorney General Jeff Sessions Jefferson (Jeff) Beauregard SessionsGOP set to release controversial Biden report Trump's policies on refugees are as simple as ABCs Ocasio-Cortez, Velázquez call for convention to decide Puerto Rico status MORE and Deputy Attorney General Rod Rosenstein Rod RosensteinDOJ kept investigators from completing probe of Trump ties to Russia: report Five takeaways from final Senate Intel Russia report FBI officials hid copies of Russia probe documents fearing Trump interference: book MORE.

However, Trump undercut that argument by telling NBC News in an interview last May that he was going to ax the FBI director “regardless of recommendation.”

“And in fact when I decided to just do it, I said to myself, I said 'You know, this Russia thing with Trump and Russia is a made-up story, it's an excuse by the Democrats for having lost an election that they should have won,’” the president said.

Despite those comments, Trump claimed last week that he did not fire Comey over the Russia investigation.

Trump has frequently attacked the ex-FBI director, calling him a "slimeball" and a "leaker" and ripping him for leaving the bureau's reputation in "tatters."

Comey recently released a book. On the subsequent press tour, he defended his time as FBI director and criticized Trump as "morally unfit" for the presidency.