A pop singer filed a police report this week accusing Corey Lewandowski, President Trump’s former campaign manager, of slapping her twice on the buttocks at a party in Washington in November.

In a phone interview on Wednesday, the singer, Joy Villa, 31, said she met Mr. Lewandowski for the first time at a party at the Trump International Hotel on Nov. 28 celebrating Mr. Trump’s election the previous year, and the two took a photograph together.

After that, Mr. Lewandowski slapped her “violently hard, enough to hurt me,” she said, adding that she told him to stop, and that she could report him for sexual harassment.

“He says, ‘Go ahead, I work in the private sector,’” Ms. Villa said. “He laughs at me and then he does it again, extra hard this time, just to show me that he wasn’t afraid. At that point I was so paralyzed by fear. I was very shocked, and my friend grabbed me and pulled me away from him.”