Donald Trump's lawyer Marc Kasowitz threatened a stranger in an email response Wednesday, according to ProPublica. Kasowitz responded with multiple emails, which were laced with a string of profane words and a hostile tone.

An unidentified man encountered an article published on ProPublica about the attorney Tuesday after it was featured on MSNBC's "The Rachel Maddow Show." The individual reached out to Kasowitz and requested that he step down from his position. The email used the subject line, "Resign Now," according to ProPublica.

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Kasowitz's emails were sent between 9:30 p.m. and 10:00 p.m. EDT. One email read: "I'm on you now. You are f——g with me now. Let’s see who you are. Watch your back, b—h."

He later responded, saying "Call me. Don’t be afraid, you piece of s—t. Stand up. If you don't call, you're just afraid."

In a third email, Kasowitz replied, "I already know where you live, I’m on you. You might as well call me. You will see me. I promise. Bro."

ProPublica confirmed that the emails came from Kasowitz’s firm. The attorney also provided a private contact number, which the publication also confirmed to belong to Kasowitz.

Kasowitz's law firm, Sitrick and Company, is one of the top firms in the United States. Michael Sitrick, the founder, issued a statement to International Business Times Thursday about the emails that went viral.

"Mr. Kasowitz, who is tied up with client matters, said he intends to apologize to the writer of the email referenced in today’s ProPublica story," Sitrick told IBT. "While no excuse, the email came at the end of a very long day that at 10 pm was not yet over."

"The person sending that email is entitled to his opinion and I should not have responded in that inappropriate manner," Kasowitz said in a separate statement to IBT. "I intend to send him an email stating just that. This is one of those times where one wishes he could reverse the clock, but of course I can't."

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Kasowitz is involved with Trump's Russia investigation, which would require him to request access for a security clearance to view confidential files. ProPublica's story on the subject, which was featured on "Rachel Maddow," claimed that the lawyer may face challenges gaining a security clearance because of his reported "history of alcohol abuse."

However, Sitrick fought the allegations in a statement acquired by The American Lawyer Wednesday, saying, "Marc Kasowitz has not struggled with alcoholism...[and] he has not come into the office intoxicated."

Kasowtiz was hired by Trump in May to serve as his personal attorney to handle allegations made against his campaign's connections to Russia, according to The Hill. Trump was reportedly advised to acquire legal representation to protect himself in the federal investigation.

Kasowitz's emails come on the heels of another email-related scandal plaguing the Trump Administration. Donald Trump Jr. received backlash from media outlets and social media alike Tuesday for allegedly colluding with Russia. Trump Jr.'s collusion incident reportedly stemmed from a string of emails with a Russian lawyer. The emails showed the Russian government's willingness to provide incriminating information on Democratic presidential nominee Hillary Clinton.

After Kasowitz's email responses were revealed to the public, Twitter users took the lawyer to task for his threatening comments, making Kasowitz a trending topic on the website.

Wow. This is the man who's supposed to be protecting the president from legal peril. https://t.co/Ccixh7fvMH — Matt Pearce (@mattdpearce) July 13, 2017

GOP supported a candidate hitting a reporter ,Trump called for violence at rallies so yes I expect Marc Kasowitz to behave like a psychopath — Jacob Gil (@jacob4kids) July 13, 2017

Funny how these #MAGA idiots are starting to be taken down by emails. Irony, anyone? "Marc Kasowitz" pic.twitter.com/A0o4IoiAsa — Doctor #Covfefe (@ShomahKhoobi) July 13, 2017

Kinda want to call Marc Kasowitz right now. — southpaw (@nycsouthpaw) July 13, 2017

Sit down, Internet, & read the late-night email threats Trump's lawyer sent a total stranger: https://t.co/T09q1ES1iK — Jesse Eisinger (@eisingerj) July 13, 2017

Supreme Court Lawyer Neal Katyal tweeted about the emails, saying "If these emails are accurate, I don't see how anyone can keep Kasowitz on as a lawyer, incl his most famous client."