Federal agents and New York Police detectives raided the Manhattan headquarters of the fashion company run by a Canadian fashion executive on Tuesday morning, seeking evidence in a sex-trafficking investigation, according to two law enforcement officials who spoke on condition of anonymity because they were not authorized to discuss an ongoing investigation.

The executive, Peter Nygard, 78, has been under investigation for at least five months by a joint child-exploitation task force of the F.B.I. and the New York Police Department, an inquiry overseen by the U.S. attorney’s office based in Manhattan. At least four women who have accused Mr. Nygard in a recent lawsuit of sexually assaulting them when they were 14 and 15 in the Bahamas have also met with the task force.

That lawsuit was filed this month. On Sunday, The New York Times detailed how a fight with his wealthy neighbor led to the lawsuit, and also showed a pattern of complaints about sexual misconduct by Mr. Nygard stretching back 40 years.

Nine women in Canada and California, mostly employees, have sued him or reported him to authorities alleging sexual harassment or assault since 1980. In addition, another nine former employees told The Times in interviews that he raped them, touched them inappropriately or proposed sex.