The audio of the joke Friedman told at a club in Houston was released Thursday on Burntorangereport.com, a blog affiliated with progressive Democratic politics, the Dallas Morning News reported. It was set in a bowling alley and used the "n-word."
Other candidates in the race for governor said that such comments are over the edge.
Friedman, who is running for governor as an independent, has also been challenged for comments he made that offended people in the black community, the newspaper said.
Earlier this month, Friedman attributed the crime increase in Houston to Hurricane Katrina evacuees, calling those responsible "thugs and crack heads," as well as saying in an interview last year that sexual predators should be locked in cells all day and made "to listen to a Negro talking to himself."
Friedman told the Morning News he feels that the criticism is an orchestrated attack and likened it to what happened to Los Angeles police Officer Mark Fuhrman during the O.J. Simpson murder trial.