Anthony Riley, a street performer who was also a contestant on "The Voice," was recently found dead in a Philadelphia apartment, E! News reports. He was 28.

In a statement obtained by USA Today, NBC expressed its sadness over Riley's death.

"We are sad over the passing of Anthony Riley," said NBC. "We offer our deepest condolences to his friends and family during this very difficult time."

"The Voice" host Carson Daly also spoke out about Riley's death via Instagram, says E! News.

E! News reports that Philadelphia authorities have yet to reveal the exact cause of Riley's death. However, USA Today and the Philadelphia Inquirer report that Riley committed suicide.

Prior to his death, Riley was a praised street performer in Philadelphia and was also a praised contestant on "The Voice," the Philadelphia Inquirer reports.

But after a month of performing on "The Voice," Riley left the show to recover from his substance abuse issues.

Following his departure from "The Voice," Riley revealed to the Philly Inquirer that he had completed rehab and was working on his debut album.

The Philadelphia Inquirer has spoken to Riley's friends and family who have all described him as a vibrant spirit.

"He'd had his problems recently. But at the heart of all that was a very kind, gentle person," said Robby Parsons, a fellow Philadelphia street performer.

He added, " [Anthony] smiled and he meant it. [He] made so many people happy, but didn't know how to make himself happy."

Riley's sister Halima also spoke to the Philadelphia Inquirer about her brother's recent death and revealed how connected and close Anthony was to the people of Philadelphia.

"The city was his family. Everybody knew him, he couldn't walk two steps without someone saying, 'Anthony, how you doin'?' " she said. "The public loved him."

Halima also revealed that the Riley family is currently making arrangement's for Anthony's memorial service. The memorial service will be open to the public.