Peter Strzok, the FBI agent removed from special counsel Robert Mueller's probe for sending text messages critical of President Donald Trump and praising Hillary Clinton also had a role in the Clinton email probe.

Strzok headed up the Clinton investigation and was the person who changed a draft of then-FBI Director James Comey's description of Clinton's actions from "grossly negligent" to "extremely careless," CNN reported Monday.

While the wording may seem an insignificant change to the uninitiated, the original "grossly negligent" could have had "potentially significant legal implications," CNN said since federal law on mishandling classified materials carries criminal penalties for "gross negligence."

Strzok also was the agent who signed the order to begin the investigation into Russian meddling, adding more fuel to criticism of the probe being politically motivated.