The surprise firing of James Comey was triggered by the ousted FBI director's recent comments on why he chose not to seek the prosecution of Hillary Clinton for using an unsecure email server, according to White House and Trump administration officials.
President Trump was angered by Comey's assertion that Clinton had no criminal intent when she mishandled highly classified information on her private server, said officials familiar with the president's thinking.
The Comey firing took center stage at a hearing of the Senate Intelligence Committee Thursday where the acting FBI director fielded questions from Democrats who suggested the dismissal was aimed at hampering an ongoing FBI counterintelligence probe into whether Russian intelligence secretly cooperated with the Trump presidential campaign last year.
During May 3 Senate testimony, Comey said one reason he recommended against a Justice Department prosecution of Clinton was that she lacked criminal "intent" when setting up the private email server that was used to transmit some classified information.
"Federal law is clear regarding classified materials: intent is not relevant [to mishandling classified information]," the White House official said.
The probe into Clinton's emails revealed that "top secret" information, including some of the nation's most closely guarded information held in what are called Special Access Programs, was transmitted on her private email server. The information included secrets on North Korea's nuclear programs and how the U.S. government targets terrorists for drone strikes.
The president was said to be upset that Comey had granted concessions to witnesses in the email probe that undermined its integrity, the officials said.