Attorney and rumored alcoholic Marc Kasowitz, who was retained by Donald Trump in response to the federal investigation into Russia’s influence on the election, is pretty tough on email. When a stranger sent Kasowitz an unsolicited but polite message advising him to drop the President as a client, Kasowitz flipped out. “Fuck you,” Kasowitz wrote, then followed up with another email: “How dare you send me an email like that.I’m on to you now. You are fucking with me now. Let’s see who you are. Watch your back, bitch.”

The man, who ProPublica describes as a retired public relations professional, cold-emailed Kasowitz after Rachel Maddow featured a ProPublica story about Kasowitz. That story said Kasowitz was not seeking a security clearance, but that if he tried to he would have a difficult time due to his alleged alcoholism and conduct that made his employees uncomfortable, including being intoxicated while “dirty dancing” with a young woman at the company holiday party.

The email read: “Marc, You don’t know me. I don’t know you. But, I believe it is in your best interest and the long term interest of the firm for you to resign from your position advising the president re. pending federal legal manners. No good can come from this and, in fact, your name may turn out to be a disparaging historical footnote to the presidency of DJT.”

Kasowitz then responded in multiple emails, demanding the man call him. “I already know where you live, I’m on to you,” he wrote.

“You might as well call me. You will see me. I promise. Bro,” Kasowitz wrote.

The man felt threatened and forwarded the emails to the FBI, ProPublica reported.