The FBI agent who was removed over allegations of anti-Trump text messages was responsible for softening language about former Secretary of State Hillary Clinton in the FBI's investigation into her private email server, CBS News has confirmed.

CBS News' Paula Reid reports that Peter Strzok, who led the investigation into Clinton's use of a private email server while secretary of state, changed the language in former FBI Director James Comey's description of how Clinton handled classified information, according to U.S. officials familiar with the matter. Strzok changed Comey's earlier draft language describing Clinton's actions as "grossly negligent" to "extremely careless." That change in wording has significant legal implications, since "gross negligence" in handling classified information can carry criminal penalties.

In his July 2016 statement about the investigation, Comey said, "Although we did not find clear evidence that Secretary Clinton or her colleagues intended to violate laws governing the handling of classified information, there is evidence that they were extremely careless in their handling of very sensitive, highly classified information."

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Strzok was dismissed from Special Counsel Robert Mueller's team after he was suspected of sending politically sensitive text messages that appeared to mock Mr. Trump. Strzok now works in the FBI's human resources department.

Multiple FBI insiders who have worked with Strzok through the years describe him as a "hard worker," and well respected in the bureau. A source in the counterintelligence division — Strzok was the second-in-charge of that division — said "you can't fake it" in counterintelligence. He developed a reputation for making tough cases. Sources tell CBS News' Jeff Pegues that, despite whatever the public perception is of the FBI, agents do not talk politics, particularly at FBI headquarters in Washington. Sources also said any public statement is crafted by several different people, and it takes a consensus to craft any statement at the FBI.

Still, the revelation of Strzok's alleged text messages, involvement in the Clinton probe and now, softening of Comey's draft in the Clinton case with possible legal implications is likely to draw intense criticism, especially from Republicans already skeptical of Mueller's investigation into Russian election meddling and any ties to the Trump campaign. Strzok's actions also give fuel to Mr. Trump's spirited rants against the FBI. Mr. Trump said the FBI's reputation is "in tatters — the worst in history" — in a series of tweets over the weekend.

The possible messages came up as the Department of Justice Office of Inspector General's reviews the actions leading up to the 2016 election, a review that has been publicly known since the beginning of the year. The OIG earlier this year announced it was reviewing the FBI probe of former presidential candidate Hillary Clinton's emails and then-FBI Director James Comey's decision to make public statements about the probe and not recommend charges. Top Republicans have already charged, based on transcripts of interviews with people close to Comey provided by the special counsel's office, that Comey drafted a statement to announce the conclusion of the investigation into Clinton before the FBI interviewed key witnesses, including Clinton herself.

Mueller's investigation of Russian election meddling has led to guilty pleas from former campaign aide George Papadopoulos and former National Security Adviser Michael Flynn. Former campaign aide Paul Manafort and his associate Rick Gates are also on trial as a result of Mueller's probe.

CBS News' Kathryn Watson contributed to this report.