The decision, which came down Monday morning in a Los Angeles courtroom, stemmed from a lawsuit filed back in 2014 by musician Marcus Gray and his team of songwriters.
Gray, best known as Flame, accused Perry, 34, of using instrumental elements of his original — and underground — song, Joyful Noise, without permission.
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The Associated Press confirmed Perry’s loss on Tuesday. According to AP reports, she was not present when the decision was made.
Although the verdict was that the Roar singer was guilty of copyright infringement, the trial is not yet complete.
On Tuesday, the penalty phase is scheduled to take place, which will determine exactly how much Perry and the other five defendants owe the plaintiffs as a result of their acts of plagiarism.
The final day of the trial is set to begin with opening arguments between both parties.
Although the defendants were sued only for the usage of specific notes and beats in Dark Horse, none of the writers were left off the hook.
Perry and Hudson wrote the lyrics together, while Juicy J provided his own verse. Neither utilized any elements from Joyful Noise, however, the jurors found that all six writers were guilty of copyright infringement.
As reported by the Associated Press, Gray’s attorneys argued that the main instrumental beat used throughout most of Dark Horse was “substantially similar” to those of Joyful Noise.
During her official testimony, nearly two weeks ago, Perry claimed that before the lawsuit came about, she had heard of neither Joyful Noise or Gray.
Perry’s own lawyer, Christine Lepera, backed her up by saying that the musical elements used in Dark Horse are so simple that it would affect the majority of songwriters.
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“They’re trying to own basic building blocks of music, the alphabet of music that should be available to everyone,” Lepera claimed during Thursday’s closing arguments.
Their musical expert claimed that the Dark Horse beat was almost as simple as the centuries-old children’s nursery rhyme, Mary Had a Little Lamb.
The jury disagreed with the defendants’ arguments, deciding that the elements used in Joyful Noise were original enough to hold copyright standards.
The music video for Dark Horse currently holds more than 2.6 billion views on YouTube alone, as opposed to Joyful Noise’s 2.4 million.
— With files from the Associated Press