RIO DE JANEIRO -- Artist Jorge Selaron may have taken his own life by setting himself on fire on the very steps of his masterpiece, a brilliantly colored public staircase that became a symbol of Rio de Janeiro, the homicide police chief said Friday.The body of Selaron, a Chilean who had adopted Rio as his home, was found early Thursday morning lying charred on the steps he had covered in a rainbow of bright tiles from all over the world as a tribute to the Brazilian people.