Anthony Riley, a Philadelphia-based street performer and former contestant on the eighth season of "The Voice," was found dead in his apartment of an apparent suicide, Philly.com reported. He was 28.

Riley's friend, Robby Parsons, confirmed to Yahoo Music that the singer was found dead on Friday in the basement of an apartment where he was staying. Parsons added that his late friend "was a gentle soul. Just a loving, caring, gentle person."

Authorities have not revealed the official cause of his death.

His sister, Halima Miley, told Philly.com that the family had yet to make the arrangements, but will have a memorial that would be open to public.

During his blind audition for "The Voice" in February, Riley quickly became a fan-favorite with his rendition of James Brown's "I Got You (I Feel Good)." His performance pushed all four judges - Blake Shelton, Adam Levine, Christina Aguilera and Pharrell Williams - to immediately turn their chairs and fight for him.

Riley chose to work with Williams, but before the Knockout Rounds, he told producers that he was struggling with substance abuse. He reportedly returned to Philadelphia to enter rehab.

"'The Voice' has been a really great source of support," Riley told Philly.com in March. "At the time, [being on the show] wasn't working for me and I felt like I needed to go, instead of taking on more responsibility than I could handle."

"We are sad over the passing of Anthony Riley. We offer our deepest condolences to his friends and family during this very difficult time," a representative for "The Voice" said in a statement.

"The Voice" host Carson Daly also paid tribute to Riley. He posted a photo of the two on Instagram with the caption, "Praying for the family and friends of Anthony Riley today. It's a heartbreaking loss. He was incredibly talented and loved to sing. God Bless him."