LOS ANGELES An investigation of Gabrielle Unions complaints of racism on the set of Americas Got Talent concluded that her allegations were unfounded, according to NBC and the shows producers. The trade publication Variety reported that Union, who is black, believed she was fired because she had asked NBC and the shows producers to respond to an environment that tolerated racist jokes and remarks. That included what Union said were multiple notes from producers saying she was wearing her hair too black for the Americas Got Talent audience. NBC sought the investigation into Union's accusations. A representative for Union didnt immediately respond to a request for comment.