The scandal over stock options backdating spread to yet another executive as the former chief executive of Monster Worldwide Inc., Andrew J. McKelvey, quit his board seat and refused to sit for questions from fellow board members.

Monster Worldwide, parent of the world’s largest job search Web site, announced McKelvey’s resignation on Monday. A board committee conducting an internal investigation had sought to interview him further following a meeting in July. Monster has received a subpoena from the U.S. attorney’s office in the Southern District of New York over stock options and has said it wants to complete its own investigation by the end of the year.