This is an interesting development:

The F.B.I. on Monday raided the office of President Trump’s longtime personal lawyer, Michael D. Cohen, seizing records related to several topics including payments to a pornographic-film actress.

Federal prosecutors in Manhattan obtained the search warrant after receiving a referral from the special counsel, Robert S. Mueller III, according to Mr. Cohen’s lawyer, who called the search “completely inappropriate and unnecessary.” The search does not appear to be directly related to Mr. Mueller’s investigation, but likely resulted from information he had uncovered and gave to prosecutors in New York.

“Today the U.S. Attorney’s Office for the Southern District of New York executed a series of search warrants and seized the privileged communications between my client, Michael Cohen, and his clients,” said Stephen Ryan, his lawyer. “I have been advised by federal prosecutors that the New York action is, in part, a referral by the Office of Special Counsel, Robert Mueller.”

If this is accurate, it is the first instance of Mueller being deterred by the mere scope of his investigation. As IANAL, I don’t even have an opinion of the propriety of seizing the protected correspondence of a lawyer and his client.