A federal judge on Tuesday sentenced the first person in special counsel Robert Mueller's investigation.

Alex van der Zwaan was sentenced to 30 days in prison and a $20,000 fine by Judge Amy Berman Jackson in Washington. The 38-year-old Dutch-born lawyer also will be under two months of supervised release for lying to Robert Mueller’s team, and is expected to leave the country after he leaves prison in Washington.

Van der Zwaan pleaded guilty in February to lying to federal prosecutors about his knowledge of communications that Rick Gates — a longtime associate of former Trump campaign chairman Paul Manafort — had with an unidentified person known as “Person A” in 2016. Van der Zwaan was told by Gates that “Person A” was a former Russian intelligence officer.

Federal prosecutors made it clear Tuesday that van der Zwaan should be used as an example for what happens when someone lies to the FBI.

“We count on people to tell us the truth,” said Andrew Weissman, a prosecutor on Mueller’s team, before the sentencing. “There are consequences for withholding documents and consequences for lying to the government.”

Van der Zwaan’s attorney asked that his client simply leave the court, pay a fine and serve no time. His wife — who is the daughter of a Russian oligarch — is sixth months pregnant, lives in London and "needs him now," argued William Schwartz of Cooley LLP.

Schwartz told the judge that van der Zwaan’s “professional life has been destroyed,” and that he has been stuck “in limbo” while living in a Washington hotel. Van der Zwaan’s attorneys argued in sentencing memos that he lied originally because he was exploring the possibility of leaving his law firm, Skadden, Arps, Slate, Meagher & Flom, to work with Manafort and Gates.

Schwartz said van der Zwaan should receive credit for returning to the U.S. voluntarily to tell the special counsel’s office that he had lied in his original interview, and to correct the record. But the judge said that was not enough.

“He lied. He knew his answers were false at the time he gave them,” Berman Jackson said before handing down the sentence. “This was not a momentary lapse.”

Van der Zwaan was seen wiping his eyes as the judge handed down the sentence.

"What I did was wrong. I apologize to the court, my wife and my family," he told the court before sentencing.

Van der Zwaan is the fourth person to plead guilty in Mueller investigation. Trump campaign aide George Papadopoulos and former national security adviser Michael Flynn pleaded guilty last year.

A total of 22 people and entities have been charged as part of the special counsel's probe, which began in May 2017 at the direction of Deputy Attorney General Rod Rosenstein.