The estate of Prince, the musician who died in 2016, pushed back against President Trump’s campaign on Thursday night after the artist’s song “Purple Rain” was played at a Trump rally that night in Minneapolis, the singer’s hometown.

On a Twitter account set up to celebrate the life of the singer, the estate said that Jones Day, the law firm that has represented Mr. Trump in election law matters and continuing lawsuits, had agreed last October that the campaign would not use Prince’s songs at rallies and other events.

The estate posted a letter it said it had received from Jones Day last year. “Without admitting liability, and to avoid any future dispute, we write to confirm that the Campaign will not use Prince’s music in connection with its activities going forward,” the letter said.