In a statement at the time, Mr. Moonves said: “I recognize that there were times decades ago when I may have made some women uncomfortable by making advances. Those were mistakes, and I regret them immensely. But I always understood and respected — and abided by the principle — that ‘no’ means ‘no,’ and I have never misused my position to harm or hinder anyone’s career.”

Shortly after the article was published, the CBS board enlisted two law firms to lead an inquiry into the claims against Mr. Moonves and the wider workplace culture at the network. The board soon after folded a separate examination of CBS News — underway since March — into the larger investigation.

The board hired Nancy Kestenbaum of Covington & Burling and Mary Jo White of Debevoise & Plimpton to conduct the inquiry. Ms. White led the Securities and Exchange Commission during the Obama administration and was previously the United States attorney for the Southern District of New York. Ms. Kestenbaum was also a federal prosecutor with the same district. The investigation into CBS News is being led by the law firm of Proskauer Rose.

Mr. Moonves had recused himself from any matters related to the investigation, and a three-member committee — Bruce S. Gordon, Linda Griego and Robert N. Klieger — has been appointed to oversee the inquiry. The makeup of that panel reflects the fractious board itself.

Mr. Klieger, a lawyer based in Los Angeles, occupies one of three CBS board seats appointed by Ms. Redstone’s family company. (In addition to Mr. Klieger, Ms. Redstone and David R. Andelman, a Boston-based lawyer who has represented the Redstone family in the past, make up the Redstone family’s board seats.)

On the other side is Mr. Gordon, a former Verizon executive and once head of the N.A.A.C.P., who is the lead independent director and has spearheaded settlement talks between the parties on behalf of CBS. Meetings between Ms. Redstone and Mr. Moonves had become so contentious that each had taken to bringing along witnesses. At a May meeting, Mr. Gordon acted in that role for Mr. Moonves. Ms. Griego, a former Los Angeles deputy mayor, is not seen as affiliated with either side.

Ms. Redstone commands both CBS and Viacom by owning 80 percent of voting rights, and the legal battle is being waged to water down that stake in CBS.