The lead attorney on President Trump’s legal team for the Russia investigation says he will apologize to the recipient of several profane and threatening emails published on Thursday by ProPublica.

“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,” Kasowitz’s spokesman Mike Sitrick said in a statement. “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,’ Mr. Kasowitz said. ‘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.’”

ProPublica published emails that Kasowitz had sent to a stranger who had sent him a critical email after a separate ProPublica story that alleged that Kasowitz has a history of alcohol abuse, that show Kasowitz threatening the recipient and using obscene language. “Watch your back, bitch,” Kasowitz tells the man, as well as calling him a “piece of shit” and saying “I already know where you live, I’m on you.”

The outlet’s previous story on Kasowitz reported that the lawyer, despite his role representing the president during a high-profile investigation, does not have a security clearance, and cited current and former colleagues outlining Kasowitz’s alleged drinking problem.