Their battle became a cottage industry for opportunists.

Investigators and lawyers tied to Mr. Bacon offered Nygard associates generous incentives to build an abuse case against the Canadian — Cartier jewelry, a regular salary or a year’s rent in a gated community, according to documents and interviews. Smaller payments filtered down to some accusers, which could be used to undermine their credibility in any court case or investigation.

Mr. Nygard used his wealth to intimidate critics and buy allies. He had employees sign confidentiality agreements and sued those he suspected of talking. Multiple women said he had handed them cash after sex, helping to buy silence. And he paid tens of thousands of dollars to people providing sworn statements to use against Mr. Bacon in lawsuits, according to court records, interviews and bank statements.

Some women said they felt exploited by both men — by Mr. Nygard for sex, and by Mr. Bacon against his enemy.

“They’re messing up people’s lives in the middle of their fight,” said Tamika Ferguson, who claims Mr. Nygard raped her when she was 16. She said she intended to join the lawsuit.

The Times interviewed all the women who eventually signed on to the suit, which identified them as Jane Does to protect their privacy. Reporters also spoke with five other women, who said Mr. Nygard sexually assaulted them in the Bahamas when they were teenagers. Three said they were under 16 at the time, the age of consent there. But two later recanted, saying they had been promised money and coached to fabricate their stories.

This isn’t the first time that Mr. Nygard, whose company sells women’s clothes at his own outlets and Dillard’s department stores, has been accused of sexual misconduct. Over the past four decades, nine women in Canada and California have sued him or reported him to the authorities. He has never been convicted.