American Idol finalist Arthur Gunn says his decision to abruptly leave the set before Sunday night's (May 23) finale was due to personal morals and unpleasant environmental experiences.

The Season 18 runner-up had been brought back for Season 19, but cut before the show named its final five. He was slated to sing with Sheryl Crow on Sunday night, and when he exited, Graham DeFranco filled in. After the show, judges had no explanation for the change; Luke Bryan praised DeFranco, Lionel Richie didn't have any idea what happened, and Katy Perry joked about a "colorful" season of American Idol, during which three finalists left the show for mysterious or personal reasons.

"It’s not necessary to state it, it is what it is, so I felt like I had to move on," Gunn writes on Instagram. "It’s not the show @americanidol to blame, they were there long before nor anyone related to show."

Later in his message, Gunn refers to unspecified confrontations and apologizes for letting his fans down. "I feel upset about it as much as you all might have," he adds.

Gunn says he'd like to make up for his missed opportunity to sing with Crow by inviting her to an upcoming concert. He characterized his decision to leave as a "last-minute decision."

Earlier during Season 19, finalist Wyatt Pike also left for personal reasons, and Caleb Kennedy was removed as a finalist after video surfaced of him sitting next to someone wearing a hood similar to those worn by Ku Klux Klan members. There were also two arrests of former Idol contestants, Doug Kiker and Cecil Ray Baker.

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