President Donald Trump on Friday issued a new threat against the father-in-law of his former “fixer” over Twitter.

Reacting to reports that former personal attorney Michael Cohen has told investigators that Trump instructed him to lie to Congress about the Trump Tower Moscow project, the president angrily wrote that Cohen was “lying to reduce his jail time!”

Even more ominously, the president added that people should “watch [Cohen’s] father-in-law,” whom the president has in the past insinuated could be prosecuted for assorted crimes.

Kevin Corke, @FoxNews “Don’t forget, Michael Cohen has already been convicted of perjury and fraud, and as recently as this week, the Wall Street Journal has suggested that he may have stolen tens of thousands of dollars….” Lying to reduce his jail time! Watch father-in-law!

— Donald J. Trump (@realDonaldTrump) January 18, 2019

Trump’s threat against Cohen’s father-in-law drew immediate gasps across the internet — with some reporters calling it a textbook example of witness intimidation.

Check out some of the reactions below.

This is witness intimidation. https://t.co/agqZ39hPwu

— Sam Stein (@samstein) January 18, 2019

You gave in to your fear.

I knew you would.

The reek of your fear-musk is so strong wolves are howling a hundred miles away. https://t.co/TD2eQJHrsP

— Rick Wilson (@TheRickWilson) January 18, 2019

I know someone whose father-in-law did jail time. It rhymes with Sri Lanka.

— pourmecoffee (@pourmecoffee) January 18, 2019

Now Trump, as President of the United States, is threatening Michael Cohen’s father-in-law as retaliation for Cohen testifying against Trump and cooperating with Mueller. Sounds like witness tampering to me.

— Eugene Gu, MD (@eugenegu) January 18, 2019

The president once again threatens a witness before congress by threatening his family. https://t.co/KX93gQDBpH

— Maggie Haberman (@maggieNYT) January 18, 2019

18 U.S.C. § 1505:

"Whoever … endeavors to influence, obstruct, or impede … the due and proper exercise of the power of inquiry under which any inquiry or investigation is being had by either House" is guilty of a felony.

— William LeGate (@williamlegate) January 18, 2019

Cohen is slated to testify before Congress, and Trump has now repeatedly made ominous suggestions regarding a member of Cohen's family. https://t.co/qSIJy3Hi04

— erica orden (@eorden) January 18, 2019

Five tweets this morning, and in every one, you’ve misspelled “I never had any conversation with Michael Cohen about his testimony concerning the Moscow Trump Tower deal.” https://t.co/aERNzFaJKG

— George Conway (@gtconway3d) January 18, 2019