LOS ANGELES — Michael Avenatti, the attorney best known for representing porn actress Stormy Daniels in lawsuits against President Donald Trump, was arrested Monday on charges that he tried to extort millions of dollars from Nike and embezzled a client’s money to pay his own expenses.

Avenatti, 48, was charged with extortion and bank and wire fraud in separate cases in New York and California. He was arrested in New York.

The allegations “paint an ugly picture of lawless conduct and greed,” said Nick Hanna, the U.S. attorney in Los Angeles. Avenatti describes himself on Twitter as an attorney and advocate, but the accusations describe “a corrupt lawyer who instead fights for his own selfish interests.”

In New York, U.S. Attorney Geoffrey S. Berman said Avenatti engaged in “a shakedown.”

“When lawyers use their law licenses as weapons, as a guise to extort payments for themselves, they are no longer acting as attorneys. They are acting as criminals,” Berman said.

The New York case accuses Avenatti of threatening to use his ability to get publicity to harm Nike. In the California case, he allegedly misused a client’s money to pay his debts and those of his coffee business and law firm. Federal prosecutors said he also defrauded a bank by using phony tax returns to obtain millions of dollars in loans.

Avenatti rose to national prominence by representing Daniels, whose real name is Stephanie Clifford, in a lawsuit to break a confidentiality agreement to speak about her alleged affair with Trump. He has also made headlines in recent weeks as the attorney representing two women who have accused R&B star R. Kelly of sexual abuse.