Latham & Watkins chairman William Voge abruptly left his post and resigned from the firm Tuesday over what Latham said was inappropriate conduct involving “communications of a sexual nature”—a move that shocked most firm insiders and startled others in the legal industry.

“Mr. Voge tendered his resignation after making a series of voluntary disclosures to the firm’s executive committee relating to his personal conduct,” the firm said in a statement. “Mr. Voge’s conduct involved the exchange of communications of a sexual nature with a woman whom he has never met in person and who had no connection to the firm.”