A top FBI agent, Peter Strzok, was removed from Bob Mueller's Russia investigation team last summer after reportedly sending text messages "that expressed anti-Trump political views," according to the New York Times.

Why it matters: Strzok "is considered one of the most experienced and trusted FBI counterintelligence investigators," per the Times. He previously played a big role in the investigation of Hillary Clinton's emails.

What happened: Mueller removed him after a discovery of texts in which Strzok and a colleague — Lisa Page, who served on Mueller's team until July — were reacting to current events in ways that could be construed as "critical" of the president. He's been reassigned to the human resources department of the FBI.

Per Washington Post: "Defenders of Page and Strzok insisted the issue is 'overblown'' and that there was no misconduct between the two."