Acting attorney general Matthew G. Whitaker received early warnings that customers were complaining that an invention-marketing company he advised might be a fraud, according to several people familiar with his role, but Whitaker vigorously defended the company and remained on its board until joining the Justice Department in 2017.

Since his appointment by President Trump last week, Whitaker has said through a Justice Department spokeswoman that he was unaware of allegedly fraudulent activities at Miami-based World Patent Marketing. The company shut down in May and agreed to pay a settlement of nearly $26 million to resolve a wide-ranging Federal Trade Commission complaint that it bilked customers…

Ed Magedson, the founder of the Arizona-based Ripoff Report, said he received a phone call from Whitaker in early 2015 after the website posted complaints about World Patent Marketing.

“He threatened me, using foul language,” said Magedson, whose website sells companies a program to improve their reputation among consumers. “He threatened to sue and to ruin my business if I did not remove the ‘false reports.’ ”