Agent Peter Strzok says he was fired from the FBI unfairly and is now suing to be reinstated

Former FBI employee and Mueller probe investigator Peter Strzok says he was fired unfairly and unlawfully, and is now suing to be reinstated, according to a lawsuit filed in federal court Tuesday afternoon.

The lawsuit contends that a "campaign to publicly vilify Special Agent Strzok contributed to the FBI's ultimate decision to unlawfully terminate him, as well as to frequent incidents of public and online harassment and threats of violence to Strzok and his family that began when the texts were first disclosed to the media and continue to this day."

The lawsuit also accuses the administration of being inconsistent with the kind of political speech it allows from people on the federal payroll.

"The Trump Administration has consistently tolerated and even encouraged partisan political speech by federal employees," the lawsuit contends, "as long as this speech praises President Trump and attacks his political adversaries."

The lawsuit claims that this behavior from the administration constitutes "viewpoint discrimination" and "is part of a broader campaign against the very principle of free speech underlying the First Amendment" that was "initiated and led by" President Trump.

"It's indisputable that his termination was a result of Trump's unrelenting retaliatory campaign of false information, attacks and direct appeals to top officials," a statement about the lawsuit from Strzok's lawyer, Aitan Goelman, said. "Today, Pete Strzok is fighting back, and sending a message that the Administration's purposeful disregard for constitutional rights must not be tolerated."

Goelman added that "FBI leaders trampled Pete's free speech and due process rights in ways that should be deeply troubling to all in government, and indeed, to all Americans."

Strzok, who began working for the FBI in 1996, was a key figure in special counsel Robert Mueller's investigation into whether or not the Trump campaign colluded with the Russian government during the 2016 election. During the course of that investigation, however, Strzok exchanged anti-Trump text messages with FBI lawyer Lisa Page, with whom he was having an affair.

The texts exchanged by Strzok and Page first came to light in late 2017 and contained angry, insulting messages aimed at then-candidate Trump and his supporters.

"Just went to a southern Virginia Walmart," Strzok says in one, "I could SMELL the Trump support." In another message, Strzok called Trump a "a f***ing idiot." In another, he promised that Trump would never get elected because "we'll stop it."

Strzok was fired for the text messages in August 2018. Page later told congressional investigators that Strzok joined the Russia investigation team with the goals of impeachment and career advancement.

The lawsuit, however, claims that Strzok was fired "because of his protected political speech in violation of his rights under the First Amendment to the Constitution of the United States." Strzok's lawyers also claim that his Fifth Amendment rights to due process were violated by the termination because he wasn't allowed to appeal the bureau's decision.