The disgraced movie mogul Harvey Weinstein used a web of private detectives, lawyers and even undercover former Mossad agents in a failed effort to stop The New York Times and The New Yorker from publishing their investigations in October into allegations of sexual harassment and assault against him.

The cloak-and-dagger undertaking, detailed in a new report on The New Yorker’s website Monday, included the use of an agent who posed as a women’s rights advocate to befriend and spy on one accuser, the actress Rose McGowan. The same agent posed as a woman with a possible allegation against Mr. Weinstein in an attempt to lure journalists into sharing information about other possible accusers, according to the magazine’s report, which relied heavily on internal Weinstein documents and emails.

A contract with one of at least three private investigation firms that Mr. Weinstein employed, Black Cube, listed its “primary objectives” as providing “intelligence which will help the client’s efforts to completely stop the publication of a new negative article in a leading NY Newspaper” and obtaining content from a book that was to include “harmful, negative information on and about the client.” The magazine identified the newspaper as The New York Times and the book author as Rose McGowan, who has stepped forward to allege that Mr. Weinstein raped her. (He has denied forcing women into “nonconsensual sex.”)

The contract, which the magazine published on its website, had as its signatory a Weinstein lawyer, David Boies, a Democratic Party stalwart who argued for marriage equality at the Supreme Court and represented Al Gore in the disputed 2000 presidential election.